COM216

Computer Troubleshooting I
Introduction to Troubleshooting

Troubleshooting is a systematic approach to problem solving that is often used to find and
correct issues with complex machines, electronics, computers and software systems. The first
step in troubleshooting is gathering information on the issue, such as an undesired behavior or a
lack of expected functionality. Other important information includes related symptoms and special
circumstances that may be required to reproduce the issue.

Once the issue and how to reproduce it are understood, the next step might be to eliminate
unnecessary components in the system and verify that the issue persists, to rule out incompatibility
and third-party causes.

Continuing, assuming the issue remains, one might next check common causes. Depending on the
particular issue and the troubleshooter’s experience, they may have some ideas. They may also
check product documentation and/or conduct research on a support database or through a search
engine.

After common causes are ruled out, the troubleshooter may resort to the more systematic and
logical process of verifying the expected function of parts of a system. One common method is the
split-half troubleshooting approach: With a problem resulting from a number of possible parts in
series, one tests half-way down the line of components. If the middle component works, one goes
to the middle of the remaining parts, approaching the end. If the test finds a problem at the mid-
point, one does a split towards the start of the line until the problem part is found. The split-half
process can save time in systems that depend on many components. Once the problem part is
identified, it may be adjusted, repaired or replaced as needed. Evidence of effective
troubleshooting is indicated when the issue is no longer reproducible and function is restored one.

The success of troubleshooting often depends on the thoroughness and experience of the
troubleshooter. That said, the majority of those who develop tech savvy are likely to have friends,
coworkers and family who call on them for help.

As you know, computer is hardware or software, so is troubleshooting.

Hardware and Software Troubleshooting

Hardware troubleshooting is the process of reviewing, diagnosing and identifying operational or

technical problems within a hardware device or equipment. It aims to resolve physical and/or
logical problems and issues within a computing hardware. Hardware troubleshooting is done by
hardware or technical support technician.

Hardware troubleshooting is generally done on hardware equipment installed within a computer,

server, laptop or related device.

Some processes within hardware troubleshooting include:

 Removing, repairing and replacing faulty RAM, hard disk or video/graphic card.
  Cleaning dusts from RAM and Video carts slot/ports and from cooling fan.
 Tightening cable and jumpers on motherboard and/or components.
 Software related hardware problems such as device driver update or installation.

Software troubleshooting is the process of scanning, identifying, diagnosing and resolving

problems, errors and bugs in software. It is a systematic process that aims to filter out and resolve
problems, and restore the software to normal operation. It is a subcategory of IT troubleshooting.
Software troubleshooting is generally done to resolve technical or source-code-related problems
in software. This can be both functional and non-functional in nature. The software troubleshooting
process starts with identifying the problem, checking on possible issues that can cause such
problems and then working on measures and alternatives to find a solution.

Troubleshooting Theory

● The importance of having a methodology.

● Six-step troubleshooting methodology.

The importance of having a methodology.

Having a troubleshooting methodology is important, especially in the IT arena. I like this quote by
Stone Gossard from Pearl Jam, "My methodology is not knowing what I'm doing and making that
work for me." While this is a great quote, not everybody can do this, especially in the technology
world.

Due to the complexity of modern computing systems, a wise technician will have and follow a
troubleshooting methodology. A formal methodology gives the technician a starting place and a
logical sequence of steps to follow. If you do not have a methodology in place, you are much more
likely to waste time and effort and create frustration—not only for yourself but also for your end
user.

Six-step troubleshooting methodology.

CompTIA recommends using a six-step troubleshooting methodology. The first step in their
methodology is to identify the problem. Step two is to establish a theory of probable cause. The
third step is to test that theory of probable cause. Step four is to develop an action plan and
implement that plan. The fifth step is to verify complete system functionality. And step six is to
document the process. In the section below, each of these steps is covered in more detail.
The six steps of troubleshooting.

1. Identify the problem.

The first thing that you need to be aware of when troubleshooting a problem is that the symptoms
are not the problem. When troubleshooting, it is critical that you actually identify the underlying
problem—what’s actually causing the symptoms to manifest themselves. To do that, you should
question the user. Ask detailed questions about when the symptoms occurred and why they may
have occurred. If the user can re-create the issue for you, this can be extremely helpful. Determine
what, if anything, has changed, which may have caused the problem. Importantly, before you take
any action, make a backup copy of the system, so that you can preserve everything as it is.

Highlights:
● Question the user.
● Remember that the symptoms are not the underlying problem.
● Determine what has changed.
● Make a backup of the system before moving on.

2. Establish a theory of probable cause.

Once you have identified the base problem that is causing the symptoms, you will establish a list
of probable causes. Once you have a list of all of the probable causes, use your technical knowledge
to prioritize that list. Your list should have the probable causes listed from most likely to least
likely. Incidentally, be sure to question the obvious. For instance, if the symptom is a power
situation at the workstation, is the power cord plugged in and, if it is plugged in, is the outlet
actually getting power? Additionally, if no probable cause can be determined, you will need to
escalate the problem to a higher level.

Highlights:
● Make a list of probable causes.
● Using your knowledge, prioritize the list.
● Question the obvious (i.e., if the symptom is a power issue at the workstation, first check
to make sure that the power cord is plugged in).
● Escalate to a higher level if a probable cause cannot be determined.

3. Test probable cause theory to determine actual cause.

Once you have established your theory of probable cause, you should take a moment to consider
whether or not you can troubleshoot the issue on your own, or if escalating it to a higher authority
is called for. If it falls within your capabilities, you will need to test your theory to determine if it
is, indeed, the actual cause. Your theory was created from the most likely probable cause, so you
need to determine how best to test it. If your theory is confirmed, you will move on to the next
step. If the theory is disproved, you will need to go back to step two or step one, as needed, and
work your way through the troubleshooting methodology.

Highlights:
● Create your theory from the most likely probable cause.
● If the theory is confirmed, move on to the next step.
● If the theory is not confirmed, go back to step two or step one (if needed).

4. Establish an action plan and execute the plan.

Once you have determined the actual cause by testing your probable cause, you will need to
establish an action plan and then execute that plan. Simple problems will probably only need
simple plans. However, if it is a complex problem, you may need to write out the plan so that you
can be sure to execute it correctly. This is another opportunity to escalate the problem to a more
senior level if necessary.

Highlights:
● Simple problems probably just need simple plans.
● Complex problems may need written out action plans.
● Escalate to a higher level if required.

5. Verify full system functionality.

After you have executed your plan, you will need to verify that the system is fully functional. If
everything works—that’s great. Based on your findings and the issue, you may find that you have
the opportunity to implement preventative measures so that the problem does not occur again. If
full system functionality has not occurred, you will need to go back to step one and continue to
work through the troubleshooting methodology.

Highlights:
● If everything works, great! If applicable, use your findings to implement preventative
measures.
● If not everything works, go back to step one.

6. Document the process.

Once everything is fully functional, documenting the process becomes important. This is where
you document findings, actions, and outcomes. When the problem occurs again, there will be
information available to walk someone through the means of troubleshooting and resolving the
issue.

This documentation also captures a history of equipment and users so that perpetual issues become
known and recorded. An important aspect of this is that both positive and negative outcomes
should be documented. This can save time during future troubleshooting and prevent others from
taking the same missteps you may have taken.

Highlights:
● Capture your findings, actions, and outcomes.
● Issues that need to be troubleshot may occur again.

Documentation provides a history of equipment and users so that problem issues are known

Computer basic troubleshooting tools

The level of troubleshooting most often performed on PC hardware is exchanging Field

Replaceable Units (FRUs). Due to the relative low cost of computer components, it is normally
not practical to troubleshoot failed components to the IC level. The cost of using a technician to
diagnose the problem further, and repair it, can quickly exceed the cost of the new replacement
unit.

Field-replaceable unit (FRU) is a printed circuit board, part, or assembly that can be quickly and
easily removed from a computer or other piece of electronic equipment, and replaced by the user
or a technician without having to send the entire product or system to a repair facility. FRUs allow
a technician lacking in-depth product knowledge to isolate faults and replace faulty components.
Customer-replaceable Units (CRU).

However, a few hardware diagnostic tools can be very helpful in isolating defective hardware
components. These tools include

 Software diagnostic
 Cable tester
 POST card
 Cable tester
 Multimeter
 Screw driver (Torx, straight-head, Philip head)
 Blower
 Chip extractor
 Needle nosed plier
 Wire cutter

Diagnostic Program
A diagnostic program is a software designed purposely for examining the state, or locating
problems with the hardware, or operating system environment that it is running on/in.
A diagnostic program is a software written for the express purpose of locating problems with the
software, hardware, or any combination thereof in a system, or a network of systems. Preferably,
diagnostic programs provide solutions to the user to solve issues.

Cable Testers

The most frequent hardware-related cause of network problems involves bad cabling and
connectors. Several specialized, handheld devices designed for testing the various types of data
communication cabling are available. These devices range from inexpensive continuity testers, to
moderately priced data cabling testers, to somewhat expensive time domain reflectometers (TDR).

Multimeter

A multimeter is a measuring instrument that can measure multiple electrical properties. A

typical multimeter can measure voltage, resistance, and current, in which case it is also known as
a volt-ohm-milliammeter (VOM), as the unit is equipped with voltmeter, ammeter, and ohmmeter
functionality.

Using a Multimeter in a PC

A number of test instruments can help you isolate computer hardware problems. One of the most
basic pieces of electronic troubleshooting equipment is the multimeter. These test instruments are
available in both analog and digital readout form and can be used to directly measure electrical
values of voltage (V), current in milliamperes (mA) or amperes (A), and resistance in ohms.
Therefore, these devices are referred to as VOMs (volt-ohm-milliammeters) for analog types, or
DMMs (digital multimeters) for digital types.

POST Cards

A POST card is a diagnostic device that plugs into the system's expansion slot and tests the
operation of the system as it boots up. These cards can be as simple as interrupt and direct memory
access (DMA) channel monitors, or as complex as full-fledged ROM BIOS diagnostic packages
that carry out extensive tests on the system.

Computer Startup Failure

Most of the time, problems can be fixed using simple troubleshooting techniques,
like closing and reopening the program. It's important to try these simple solutions before
resorting to more extreme measures. If the problem still isn't fixed, you can try other
troubleshooting techniques.
Common Computer Startup Problems and Solutions

These situations often fall into one of the categories below:

No power on:
This is used to describe a laptop or desktop where the power LED lights do not display and there
is no image on the screen. For a laptop, a broken charger connector, failed motherboard, failed
power supply or dead battery will prevent startup. Test using a replacement charger and battery.

For a desktop, a failed motherboard or failed internal power supply will prevent power on. Some
desktop/tower computers also have a power switch on the back of the computer that must be turned
on in addition to the front panel power switch.

For desktop computers and servers connected to a “UPS” (uninterruptible power supply) the UPS
unit relies on the internal battery power to start unit, even when there is sufficient utility power
from an outlet. When a UPS cannot be turned on, this is an indication the internal batteries are
failed and require replacement.

Power on, no video:

This is used to describe a laptop or desktop where the power LED lights indicate that the computer
is turned on but nothing displays on the screen. For a laptop, power on without any image on the
screen can be caused by a failed CCFL backlight inverter or failed LCD panel.

For a desktop, when no image is present on the screen, the screen may be failed. Also, a loose
power cord or monitor cable may prevent an image from displaying. Test by replacing with a
known good working monitor.

When a computer is using both the Hibernate and Standby power saving options, it is possible for
a computer to first go into standby mode and then hibernate and shutdown. This can result in a
blank screen when the computer resumes from Hibernate, and then fails to resume from standby
mode, leaving the user with a black screen and no cursor. This can be resolved by forcing a
shutdown by holding down the power button for more than 4 seconds and then turning the
computer back on.
Power on, scrambled video:
This is commonly seen on laptops with a cracked LCD panel. LCD panel replacement is required.
This is rarely seen on desktops but occurs where there is bad video memory or a failing video card.

Power on, Windows XP restarts:

The default behavior in Windows XP is to restart when there is an error that stops Windows from
working. The result is that Windows will briefly flash a blue screen with white writing, and then
restart the computer. The restarting can be caused by a bad motherboard, overheating CPU, failing
RAM memory, hard disk drive error, virus, or corrupt NTFS file system.

Any of these problems will generate a Windows stop code 0x7B, preventing Windows from
starting up until the problem is diagnosed and resolved. The automatic restart option can be
disabled to allow display the stop error code, which will aid in diagnosing the type of problem.

Power on, Windows Vista/7/8 startup repair:

Windows Vista/7/8 try to perform a startup repair that checks for common problems and tries to
fix them. This startup repair can take 5-20 minutes and will restart Windows when finished
attempting the repairs. For problems including overheating, failed components, bad RAM, virus
and hard disk drive error, the startup repair will not resolve the startup failure and Windows will
continually repair and restart until the problem is diagnosed and resolved.

Causes of computer startup failure include

i. Bad electrical connection
ii. Hardware failure
iii. Bad power supply
iv. Boot sector virus
v. Incorrect BIOS Boot Sequence
vi. Damaged Hard Disk or Partition
vii. Operating System failure

A. Problem: Power button will not start computer

 Solution 1: If your computer does not start, begin by checking the power cord to
confirm that it is plugged securely into the back of the computer case and the power
outlet.
  Solution 2: If it is plugged into an outlet, make sure it is a working outlet. To
check your outlet, you can plug in another electrical device, such as a lamp.
 Solution 3: If the computer is plugged in to a surge protector, verify that it is
turned on. You may have to reset the surge protector by turning it off and then
back on. You can also plug a lamp or other device into the surge protector to verify
that it's working correctly.

 Solution 4: If you are using a laptop, the battery may not be charged. Plug the AC
adapter into the wall, then try to turn on the laptop. If it still doesn't start up, you
may need to wait a few minutes and try again.

B. Problem: The screen is blank

 Solution 1: The computer may be in Sleep mode. Click the mouse or press any key
on the keyboard to wake it.
 Solution 2: Make sure the monitor is plugged in and turned on.
 Solution 3: Make sure the computer is plugged in and turned on.

 Solution 4: If you're using a desktop, make sure the monitor cable is properly
connected to the computer tower and the monitor.

Computer booting

Computer booting (also known as booting up) is the initial set of operations that a computer system
performs when electrical power is switched on. The process begins when a computer that has been
turned off is re-energized, and ends when the computer is ready to perform its normal operations.
On modern general purpose computers, this can take tens of seconds and typically involves
performing power-on self-test, locating and initializing peripheral devices, and then finding,
loading and starting an operating system. Many computer systems also allow these operations to
be initiated by a software command without cycling power, in what is known as a soft reboot,
though some of the initial operations might be skipped on a soft reboot. A boot loader is a computer
program that loads the main operating system or runtime environment for the computer after
completion of self-tests.

The computer term boot is short for bootstrap or bootstrap load and derives from the phrase to pull
oneself up by one’s bootstraps.
In computing, booting is the process of starting a computer. It can be initiated by hardware such
as a button press, or by a software command. After it is switched on,
a computer's central processing unit (CPU) has no software in its main memory, so
some process must load software into memory before it can be executed.

Six steps of the booting process are BIOS and Setup Program, The Power-On-Self-Test (POST),
The Operating System Loads, System Configuration, System Utility Loads, and Users
Authentication.

Booting Process

Here we represent the booting process of the computer with a diagram.

Booting is the process of switching on the computer and starting the operating system. 6 steps in
the booting process are BIOS and Setup Program, The Power-On-Self-Test (POST),
The Operating System Loads, System Configuration, System Utility Loads, and Users
Authentication.

 1: BIOS and Setup Program

 2: The Power-On-Self-Test (POST)
 3: The Operating System (OS) Loads
 4: System Configuration
 5: System Utility Loads
 6: Users Authentication

Booting Process Of Computer Step By Step

Here is the explanation of the booting process steps for more clarity.
Step 1: BIOS and Setup Program

 ROM (read-only memory): it is a permanent and unchanging memory also

 BIOS (basic input/output system ): the part of the system software that includes the
instructions that the computer uses to accept input and output
 Load: to transfer from a storage device to memory. The ROM loads BIOS into the computer’s
memory

 Setup program: a special program containing settings to control

hardware. Furthermore, the program can only be accessed while the BIOS information is
visible

Step 2: The Power-On-Self-Test (POST)

 POST (Power-On Self-Test): a series of tests conducted on the computer’s main

memory, input/output devices, disk drives, and the hard disk.
 BIOS conducts Power-On-Self-Test to check the input/ output system for operability.
 The computer will produce a beeping sound if any problem occurs. An error message will also
appear on the monitor

Step 3: The Operating System (OS) Loads

BIOS searches for the operating system.

 Setting in CMOS: complementary metal oxide semiconductor determines where to look for
the operating system.
 In this step, the operating system’s kernel is also loaded into the computer’s memory.
 The operating system takes control of the computer and begins loading system configuration
information.

Step 4: System Configuration

 Registry: a database to store information about peripherals and software

 Peripheral: a device connected to a computer
 Drive: a utility program that makes peripheral devices function properly
 The operating system’s registry configures the system.
 In this step, drivers are also loaded into memory.

Step 5: System Utility Loads

 System utilities are loaded into memory.

 Volume control
 Antivirus software
 PC card unplugging utility

Step 6: Users Authentication

 Authentication or user login occurs
 Username
 Password
The above-mentioned steps play an important role in booting a computer. After all this process,
the user interface starts, enabling user interaction with the computer and its programs also.

There are two Types of Booting

Two types of booting are cold booting and warm booting.

Booting is the process of switching on the computer and starting the operating system. When a
computer is switched on, The boot process loads the operating system into the
main memory (RAM) installed inside it. Types of computer booting are Cold Booting And Warm
Booting.

1) Warm Booting: A warm boot (also called a "soft boot") is the process of restarting a
computer. It may be used in contrast to a cold boot, which refers to starting up a computer that
has been turned off. Warm boots are typically initiated by a "Restart" command in the operating
system.

2) Cold Booting: Cold booting is the process of starting up a computer that is switched off.
Usually, it is performed by pressing the power button on the computer. Cold booting performs
the “Power on Self-Test” (POST). It is a series of system checks at the beginning of the boot
sequence.

POST

POST (Power-On Self-Test) is the diagnostic testing sequence that a computer's basic input/output
system (or "starting program") runs to determine if the computer keyboard, random access
memory, disk drives, and other hardware are working correctly. It is a succession of built-in
diagnostic tests performed when turning on a computer system .

If the necessary hardware is detected and found to be operating properly, the computer begins
to boot. If the hardware is not detected or is found not to be operating properly, the BIOS issues
an error message which may be text on the display screen and/or a series of coded beeps, depending
on the nature of the problem. Since POST runs before the computer's video card is activated, it
may not be possible to progress to the display screen. The pattern of beeps may be a variable
numbers of short beeps or a mixture of long and short beeps, depending on what type of BIOS is
installed.
Short for power-on self-test, the POST is a test the computer must complete verifying all
hardware is working properly before starting the remainder of the boot process. The POST process
checks computer hardware, like RAM (random access memory), hard drive, CD-ROM
drive, keyboard, etc., to make sure all are working correctly.

If all hardware passes the POST, the computer continues the boot up process and may generate a
single beep sound as well. If POST is unsuccessful, it generates a beep code to indicate the error
encountered and the computer will not boot up. All POST errors are relating to hardware issues
with one of the components in the computer.

BIOS

BIOS stands for basic input output system. It is the very first thing a computer accesses when it is
turned on. The BIOS tells the computer all the information it needs for it to run: information such
as memory, hardware and basic processor settings. The boot-up process the BIOS uses is called
the POST. The BIOS resides in a ROM (Read Only Memory) chip that is installed directly on the
motherboard. In most cases, the BIOS chip is installed in a removable socket so it can be replaced.
The information in the BIOS can often be updated and changed by performing an operation called
a flash.

Symptoms of a crashing BIOS

Since the BIOS is the first thing the computer accesses when booting, the symptoms of a BIOS
crash or corruption will be usually evident during the POST. You may see strange error messages
or hardware may not be recognized properly. Another symptom of a BIOS problem is the
computer’s RAM, normally counted during the POST, not being counted correctly or producing
an error message during the count. The most common symptom of a BIOS corruption or crash is
the BIOS simply refusing to POST. If the computer turns on but doesn’t boot any further, you may
have a BIOS problem.

Troubleshooting BIOS

Problems with the BIOS may be fixed by checking the settings in the BIOS setup menu. This can
be accessed during the POST by hitting the setup button, usually "F2" or the "DELETE" key, when
prompted.

BIOS beep codes for Award/Phoenix

 No errors detected during the self-
1x short test

2x short Non-specified error; more details

displayed on screen

Continuous Memory or graphics card not

beep detected

Repeated Insufficient power supplied to the

short beeps motherboard

1x long RAM error

1x long, 1x Motherboard error

short

1x long, 2x Graphics card error

short

1x long, 3x Keyboard controller failure;

short graphics card error (in later BIOS
versions)

3x long Communication error between

keyboard and motherboard

BIOS beep codes for AMI

1x short Incorrect interaction between RAM and motherboard

1x long No errors detected during the self-test

Continuous beep Power supply error

1x long, 1x short Fault on motherboard

 1x short Incorrect interaction between RAM and motherboard

1x long, 2x short Graphics card not detected

1x long, 3x short Video memory error

2x short Parity error in the first 64 kB of memory

2x long, 2x short Video memory error

3x short, 3x long, 3x Defective RAM; RAM must be replaced

short

5x short Problem with processor

6x short Cannot enter BIOS in safe mode

7x short Processor or graphics card error

8x short Display memory error in graphics card

9x short CMOS battery error

10x short Error in shutdown register of CMOS RAM

11x short Error in external cache memory

BIOS beep codes for IBM

1x short No errors detected during the self-test

2x short Error during the POST; more details displayed on screen

No beep Power supply/system board/processor error; often related to

power supply
 1x short No errors detected during the self-test

Continuous Power supply/system board/keyboard problem

beep

Repeated Power supply or system board problem

short beeps

1x long, 1x System board problem

short

1x long, 2x Graphics card problem (Mono/CGA video error)

short

1x long, 3x Graphics card problem (EGA video error)

short

3x long Keyboard problem

BIOS beep codes for DELL

Dell beep codes are all the same length. You need to listen for how often a beep is repeated after
a short pause. This is indicated by the figures and dashes in the following table. For example, “1 –
2” means “Beep – Beep Beep”. The beep codes in the table below are used by Dell-OptiPlex
systems. Other Dell systems such as Inspiron or Vostro incorporate flashing LEDs to communicate
error messages.

1–1–2 Microprocessor register failure

3–2–4 Keyboard controller test failure

3–3–1 NVRAM power loss

3–3–4 Video memory test failure

3–4–1 Screen initialization failure

 1–1–2 Microprocessor register failure

4–2–2 Shutdown failure

4–4–4 Cache test failure

BIOS beep codes for Macintosh

One beep, repeating

every 5 seconds No RAM installed

3x short, 5-second RAM did not pass data integrity check

pause, 3x short

1x long while you An EFI ROM update is in progress

hold down the power (only applicable to computers
button manufactured before 2012)

3x long, 2x short, 3x EFI ROM error or Mac is in EFI ROM

long recovery mode

CHECK DISK
CHKDSK is a command that can be run in Command Prompt to verify the logical integrity of the
file system. The full name of CHKDSK is actually checkdisk; as the name suggests, it is designed
to check disk for errors and then fix it. CHKDSK works on the basis of certain partition file system
to create and display the disk status. If CHKDSK is typed without any parameters, the disk status
in the current drive will be displayed to people.
CHKDSK utility can be found in all Windows versions, such as, Windows XP/7/8/10 and DOS.
Moreover, you can even run this command from a Windows installation disc.

The chkdsk command lists and corrects errors on the disk. Used without parameters, chkdsk will
display the status of the disk in the current drive. The parameters are as follows:

 drive : (specifies the drive that you want to chkdsk). For example, chkdsk C:
 /p (Performs an exhaustive check)
 /r (locates bad sectors and recovers readable information. Implies /p)
 /f Finds and repairs errors. For example, chkdsk /f C
Symptoms of hard drive failure
i. Frequent but irregular crashes, especially while booting up Windows®
ii. Frequent and Intermittent Boot Errors
iii. Folder and file names that have been scrambled and changed
iv. Disappearing files and folders
v. Really long wait times to access folders and files
vi. Garbled output from open files or printing
vii. Hard drive grinds away constantly because of noisy bearings
viii. Long Access Times
ix. Hard Drive Clicking

Before assuming a hard disk has failed, the isolation test to determine whether the problem is the
hard disk, its power cable, or its data cable is as follow:

i. Shut down the computer. (optional)

ii. Disconnect the power supply from AC power.
iii. Open the system.
iv. Locate the power cable running between the hard disk and the power supply.
v. Disconnect the power cable from the power supply.
vi. If the power cable used a splitter or converter to provide power to the drive, plug the drive
directly into the power supply (if possible). If that is not possible, replace the splitter or
converter and make sure it is securely plugged into the power supply lead and the drive.
vii. Reconnect the power supply to AC power.
viii. Restart the computer.
ix. If the drive is still not working, repeat steps 1 and 2.
x. Reconnect the drive to the original power cable (and splitter or converter).
xi. Remove the data cable from the hard disk drive and the computer and Install a known-
working data cable.
xii. Repeat steps 7 and 8.
xiii. If the drive is still not working, the drive has failed. Replace it.

Steps involve solving disconnected or loose SATA (Serial advanced technology attachment), an
interface for transferring data between a computer's central circuit board and storage devices.)
drive power cable is as follows

i. Shut down the computer.

ii. Disconnect the power supply from AC power.
iii. Open the system.
iv. Check the hard disk drive or SSD for loose or disconnected cable(s).
v. Check the motherboard for loose or disconnected SATA data cables.
vi. Securely plug the cable(s) into place
Importance of hard disk partitions
i. In case of system failure, your data is less likely to be affected
ii. You can use multiple operating systems on the same pc
iii. Improved performance
iv. Organizing your data is much easier

Symptoms of RAM Failures include

i. Windows doesn’t start showing different error messages each time.

ii. Windows crashes (blue screen) or freezes frequently.
iii. Windows crashes as soon as you try to start a program.
iv. Unexplained random crashes and freezes without error messages

Sound Failure Symptoms in computer

Some of the problems associated with the sound in computers are as follows:

i. No sound from the computer's speakers or headphones.

ii. A sound seems to be played, but not heard.
iii. A sound is played, but then stops suddenly.
iv. The sound skips or misses in some areas.
v. The sound is distorted or scratchy.
vi. The computer stops responding (hangs) when a sound is played.
vii. The computer restarts when a sound is played.

An error message is received when you try to play sound. For example, you may receive any one
of the following error messages:

i. MIDI output error detected.

ii. No wave device that can play files in the current format is installed.
iii. The CD Audio device is in use by another application.
iv. WAV sound playback error detected.
v. Your audio hardware cannot play files like the current file.

Troubleshooting procedure:

If you added hardware or software to your computer immediately before the issue started, remove
the added hardware or software. Be sure to turn off the computer before removing hardware. As
with any problem that arises with computers, reversing a process that started a problem may correct
the problem.
Check the following points:

 Are the speakers turned on and have power?

Try unplugging the speaker power adapter and keep it disconnected for 30 seconds or so, then plug
it back in.

Try plugging a known working item (such as a lamp) to check the wall outlet for power.
Check to insure that the Mixer Control volumes are set to 3/4 volume and are not muted.
Analog or digital can be set in the Mixer Controls, depending on the type of sound card and
speakers used.
Make sure that all connections to all speakers are fully seated. Usually, these plugs click twice
before the fully seat.

11. Try plugging in a known working set of head phones to ensure that the sound card is
functioning.

12. Try plugging in the speakers to a known working portable CD player that will accept the same
connection. This will determine if the speakers are working.
13. Go to: Start>> Control Panel>> Administrative Tools>> Component Services>> Services.
Make sure audio is enabled.
14. Go to: Start>> Control Panel>> Sounds and Audio Device Properties. Be sure that the "Mute"
checkbox is unchecked.

Volume Control settings

The procedure for setting up the audio controls is outlined below:

1. Click on the Start button and continue to the Control Panel section of the Start menu
2. Control Panel Window will appear
3. In the Control Panel window find Sounds, Speech, and Audio Devices section, click on it
4. The Sounds, Speech, and Audio Devices window will appear In the Sounds,
5. Speech, and Audio Devices window find the Sounds and Audio Devices section, click on
i

How to Change Playback Options

1. The Sounds and Audio Devices panel will appear

2. Find the Audio section tab (top line of buttons), click on it
3. The Audio Settings section will open
4. In the Sound Playback section from the drop down menu, select thedevice
5. Click on the Volume button below the drop down menu
 6. The Volume Control panel will appear Find the Options menu button, click on it Click on
the Properties section

Troubleshooting Keyboard Problems

Most of the circuitry associated with the computer's keyboard is located on the keyboard itself.
However, the keyboard interface circuitry is located on the system board. Therefore, the steps
required to isolate keyboard problems are usually confined to the keyboard, its connecting cable,
and the system board.

Keyboard Symptoms

Typical symptoms associated with keyboard failures include the following:

 No characters appear onscreen when entered from the keyboard.

 Some keys work, whereas others do not work.
 A Keyboard Error—Keyboard Test Failure error appears.
 A KB/Interface Error—Keyboard Test Failure error appears.
 An error code of six short beeps is produced during bootup (BIOS dependent).
 The wrong characters are displayed.
 An IBM-compatible 301 error code appears.
 An Unplugged Keyboard error appears.
 A key is stuck.

Basic Keyboard Checks

The keys of the keyboard can wear out over time. This might result in keys that don't make good
contact (no character is produced when the key is pressed) or that remain in contact (stick) even
when pressure is removed. The stuck key produces an error message when the system detects it;
however, it has no way of detecting an open key.

An unplugged keyboard, or one with a bad signal cable, also produces a keyboard error message
during startup. Ironically, this condition might produce a configuration error message that says
"Press F1 to continue."

If the keyboard produces odd characters on the display, check the Windows keyboard settings in
Device Manager. Device Manager is located under the System icon (found in Control Panel) in
Windows 9x and Windows Me. In Windows 2000, the path is similar—Control Panel, System,
Hardware tab. However, in both Windows 2000 and Windows XP, Device Manager is usually
accessed through the Computer Management console. If the keyboard is not installed or is
incorrect, install the correct keyboard type. Also, be certain that you have the correct language
setting specified in the Keyboard Properties dialog box (found by double-clicking the Keyboard
icon in Control Panel).
Keyboard Hardware Checks

If you suspect a keyboard hardware problem, isolate the keyboard as the definite source of the
problem (a fairly easy task). Because the keyboard is external to the system unit, detachable, and
inexpensive, simply exchange it with a known-good keyboard.

If the new keyboard works correctly, remove the back cover from the faulty keyboard and check
for the presence of a fuse in the +5V DC supply and check it for continuity. Neither the older five-
pin DIN nor the six-pin PS/2 mini-DIN keyboards can be hot-swapped. Disconnecting or plugging
in a keyboard that has this type of fuse while power is on can cause the keyboard to fail. If the fuse
is present, simply replace it with a fuse of the same type and rating.

If replacing the keyboard does not correct the problem, and no configuration or software reason is
apparent, the next step is to troubleshoot the keyboard receiver section of the system board. On
most system boards, this ultimately involves replacing the system board.

These are some symptoms that may be caused by the CD ROM drive.

Symptom Remedy
CD ROM drive cannot be  Check that the power and controller cables are securely
accessed and the attached to the drive.
Light does not go on  Verify that pin #1 of the controller cable is matched to pin
#1 on the drive and on the motherboard.
 The operating system may not be configured to use or
"see" the drive.
 If it never worked, verify that the jumpers on the drive are
set correctly.

CD ROM drive cannot  The CD may be damaged or unreadable.

be accessed but the light  Try removing and reinserting the disk.
does go on  Try cleaning the CD.
 Verify that pin #1 of the controller cable is matched to pin
#1 on the drive and on the motherboard.
 If it never worked, verify that the jumpers on the drive are
set correctly.
The drive drawer does not  Press the button once and wait at least a minute.
open  In Windows, go to "My Computer", right click on the
CD-ROM drive and choose "Eject" from the menu.
 With the computer unplugged, you can open most CD-
ROM drawers with a unwound paper clip. Poke it, as
straight as possible, into the hole and push with moderate
force (the paper clip may bend a little) to force the drawer
open a half inch. Now pull the drawer the rest of the way
open.
 If the problem persists, check that the power connector
and controller cable are securely connected to the drive.
 A CD may be jammed or broken inside the drive. Access

may require the removal of the drive's outer case. If this is

necessary, it is very likely that the drive will have to be
replaced.

Spinning sound is  The CD may be damaged or unreadable.

Heard  Try removing and reinserting the disk.
and then stopping  Try cleaning the CD.
repeatedly  Verify that pin #1 of the controller cable is matched to pin
#1 on the drive and on the motherboard.
 If it never worked, verify that the jumpers on the drive are
set correctly.
The drive seems to  Is the drive on the same controller cable as the primary

transfer data too slowly hard drive? If so, performance will be slowed because

only one device can communicate at a time. Move it to

the second IDE controller.

Replacing a CD ROM Drive

Incase the CD ROM drive needs replacement, The procedure for replacing a CD ROM drive is as
follows:

1. Remove the side covers of the PC and remove the defective CD ROM drive as shown in the
figure.
2. Adjust the jumpers on the back of the CD ROM (if necessary) as shown in the figure.
3. Replace the new CD ROM drive by sliding it in to the bay as shown in the figure
4. Connect the power supply cable to the CD Rom drive as shown in the figure.
5. Connect the ribbon cable as shown in the figure.
6. Connect the audio cable (if necessary) to the drive as shown in the figure. Connect the other end
of this audio cable to the sound card.
7. Secure the drive in to the drive bay as shown in the figure and replace the computer cover.
8. Power up the computer.

Device Connections and Ports

All devices connect to the motherboard in some way. Internally they connect to the PCI
slots, PCI express slots, IDE interface, SATA interface, or some other bus system.
External devices connect to a computer using Input/ Output (I/O) ports.

I/O ports transmit data via serial or parallel connections that can be manipulated from
within the BIOS. I/O ports send and receive data in the form of bits (0s and 1s), which can
be transmitted in serial or parallel.

Ports
A port is basically an interface between the computer and the output devices like printer,
speakers, mouse, etc. Besides, it can be of many types like serial port, parallel port, USB Port,
etc. Moreover, we know that the processing speed of the CPU and memory is much faster than
the input/output devices. Hence, it is important to take care that the data lines do not engage for a
long time else it can affect the overall performance. Therefore, we connect these devices through
the ports.
Characteristics of Computer Ports

 We use the ports to connect external devices like printers, USB, speakers, etc.
 Ports in other words are slots on the motherboard to which we connect the external devices.

Types of Ports

The ports are of different types as follows:

 Serial Port
 Parallel Port
 PS/2 Port
 USB Port
 VGA Port
 Game Port
 Modem Port etc.

Serial Transmission

Serial transmission refers to the transmission of data down a single wire one bit at a
time.

Among other applications, serial ports are often used to allow a technician to interface
with the operating system of a device by typing commands in a terminal window that is
spawned by software that communicates with the device through the serial connection.

Serial Port

Serial Port is an asynchronous port on the computer used to connect a serial device to the computer
and capable of transmitting one bit at a time. Serial ports are usually identified on IBM compatible
computers as COM (communications) ports. For example, a mouse might connect to COM1 and a modem
to COM2.

Serial Port Issues (And Solutions)

Even a minor serial port problem can become a major issue. And without the skills and know-
how to identify and resolve a serial port problem, a business could suffer due to ineffective serial
connections.

Here’s a closer look at five common serial port problems, along with ways to resolve such
issues:

1. Incorrect Communication Parameters

The most common cause of serial port communication problems is incorrect communication
parameter settings. To operate correctly it is essential that both devices are set up with the same
communication parameters, which includes baud rate, parity, number of data bits, and number of
stop bits.

2. Incorrect Serial Cable

Is a serial cable connected between a PC and a serial port? If a user leverages the wrong cable, he
or she will be unable to establish a connection.

A serial port serves as a physical connector on the back of a computer that allows for the input
and output of data, and there are two different types of serial port connectors: 9-pin and 25-pin.
As such, the correct cable and/or adapter is necessary to ensure the proper connection at all
times.

Another important cable characteristic that is often overlooled is whether the application requires
a “null-modem” or “straight through” cable. Null modem cables typically have a female
connector on each end and straight through cables have a female connector at one end and a male
at the other. Be sure to use the correct cable for your particular application.

3. Bad Serial Cables

What happens if a serial cable is not working properly? This issue can limit data transmission
and retrieval but can be easily fixed by replacing the serial cable.

In many cases, a loose cable may simple need to be reconnected to a serial port. But in other
situations, an ineffective cable will need to be replaced immediately, especially if the serial port
is functioning properly.

View the Stratus Engineering product line for industry leading solutions.

4. Software Conflicts

A software driver may result in a non-working serial port. If this driver is not installed properly
or is not compatible with a serial port, it may cease to perform.

Re-installing the affected drivers can help a user overcome this problem. In addition, a user may
be able to alter the serial port settings to ensure this issue is fully resolved.

5. Faulty Wiring

When connecting a control system to a device, incorrect wiring can be problematic at times.

Typically, the control system’s transmit and ground pins must be connected to the connected
device’s Receive and Ground pins, respectively. If a connected system needs to receive a
response from a controlled device, however, a third wire also may be connected as well.
Parallel Port

A parallel port is an interface allowing a personal computer (PC) to transmit or receive data down multiple
bundled cables to a peripheral device such as a printer. The most common parallel port is a printer port
known as the Centronics port. A parallel port has multiple connectors and in theory allows data to be sent
simultaneously down several cables at once. Later versions allow bi-directional communications. This
technology is still used today for low-data-rate communications such as dot-matrix printing.

Parallel ports perform a parallel communication interface. Moreover, it can transfer multiple bits at a
time. Besides they also connect devices like printers and scanners. We can also call them printer port.
Furthermore, they contain 25 pins, and the speed of data travel is 150-kilo bits per second.

Failures of the serial, parallel, and game ports tend to end with poor or no operation of the
peripheral. Generally, there are only four possible causes for a problem with a device connected
to an I/O port:

 The port is defective.

 The software is not configured properly for the port (that is, the resource allocation,
speed, or protocol settings do not match).
 The connecting signal cable is bad.
 The attached device is not functional.

Difference Between Serial Port and Parallel Port

Serial Port Parallel Port
 It performs serial  It performs parallel
transmission. transmission.

 The transmission speed is  The transmission speed is

lesser than the parallel port. higher than the serial port.

 The number of wires is

 The number of wires is less. more as compared to the
serial port.

 It can transmit multiple

 It transmits a single stream
streams of data which
of data which means bit by
means multiple bits
bit transmission.
transmission.
  Serial ports involve male  Parallel ports involve
ports. female ports.

 Devices using serial ports

 Devices using parallel ports
are mainly modems,
are mainly printers, hard
connecting devices,
drives, zip-drives, CD-
controllers, security
ROM drives, etc.
cameras, etc.

USB Port

A USB port is a standard cable connection interface for personal computers and consumer electronics
devices. USB stands for Universal Serial Bus, an industry standard for short-distance digital data
communications. USB ports allow USB devices to be connected to each other with and transfer digital
data over USB cables.

USB connector types

USB connectors come in different shapes and sizes. Most of the USB connectors, including the
standard USB, Mini-USB, and Micro-USB, have two or more variations of connectors. Further
information on each type is provided below.

A computer's USB ports might not work because of internal hardware issues, improper software
configuration, problems with a previously connected device or use of an incompatible USB extension
cable.
Causes of USB Port Failure

Assuming the currently connected device is not the source of the problem, there are several potential
causes for Universal Serial Bus (USB) ports not working. A computer's USB ports might not work because
of internal hardware issues, improper software configuration, problems with a previously connected
device or use of an incompatible USB extension cable.

Previously Connected Device

Some causes relate to the previous device connected to a port. Microsoft's website indicates that
USB ports may not work after you connect a defective accessory to the computer, even after
disconnection. To correct this, shut down the computer and start it up again. Another problem is
that rapidly connecting and disconnecting an accessory might cause the USB port not to work.
Reconnecting the device and scanning for changes to the hardware, restarting the system or
resetting the USB controller may correct this problem and make the ports work again, according
to Microsoft.

Software Configuration
Other major causes of USB ports not working include invalid software and operating system
settings. The problem may stem from these settings if you recently added a new port or device,
installed a new operating system or made other significant changes to the computer. Settings in
the Control Panel, Device Manager or main setup program may prove necessary. It's also
possible that the computer still needs drivers for the USB port, device or controller. Additionally,
the computer could have a virus that interferes with the work of certain accessories or ports.

Hardware Problems
Although issues with software and accessories tend to produce more computer problems than
actual hardware failure, it cannot be ruled out. If the computer uses a USB card installed in one
of the expansion slots, it could have become loose or the slot might have failed. A wire running
from the USB port to the motherboard may be detached. Other potential hardware causes include
damage to the ports or a defunct USB controller. It's also possible that the ports simply need
cleaning.

Other Causes
Connecting the wrong type of USB extension cable may cause the ports not to work. Using a
high-speed accessory with a low-speed USB cable causes this to happen, according to Microsoft.
Some old operating systems do not support USB, so the ports will do nothing more than supply
power to an accessory. For more possible causes, refer to the instruction manuals of the
computer, the accessory and any add-on USB hardware.
Printer

A printer is an external hardware output device that takes the electronic data stored on a computer or
other device and generates a hard copy. For example, if you created a report on your computer, you could
print several copies to hand out at a staff meeting. Printers are one of the most popular computer
peripherals and are commonly used to print text and photos.

Causes of printer failure

Stuck Print Spooler

When you print a document, the file is stored temporarily on your computer. Your printer
retrieves the job when it’s ready and prints the document. If the Windows print spooler service
gets stuck, jobs that you send to the printer will not print, and the printer itself will not respond in
any way. Restarting the spooler service usually resolves the problem. Click "Start," type
“services” (without quotes) in the box and click “Services” when it appears in the results. Right-
click “Print Spooler” and click “Restart.”

Driver Issue
A device driver is software that facilitates communication between the operating system and the
device. If a printer’s driver is malfunctioning, or if no driver is installed, the printer either will
not respond or will give you printouts with gibberish on them. A printer with no installed driver
will show up in Devices and Printers with an exclamation mark next to it. You can obtain printer
drivers from the manufacturer’s website, Windows Update or the installation disc that came with
the printer.

Overuse
All printers have a monthly recommended page volume. This information is usually available in
the user manual, on the printer’s retail box or on its online product page. If you consistently
exceed this recommended volume on a printer, you’ll eventually encounter repeated jamming,
and internal parts such as paper pickup rollers will fail much quicker than they normally would.
You should not, for example, have an entire department printing to a small desktop laser printer.
When shopping for office printers, consider how many employees will be using it and what their
monthly print requirements will be before deciding on which model to buy.

Consumables Issue
Most printers will stop working when they’re out of paper, ink or toner, or if the unit detects an
issue with the ink or toner cartridge. When this occurs, you might receive an error message or
notice blinking green or amber lights on your printer. If you have a larger high-volume office
printer, the unit might also halt if the waste toner bottle -- a repository for unused toner particles
during the print process -- gets full. Some laser printers will also stop working if an internal
sensor determines that the drum or other part has reached the end of its serviceable life.

MODEM

Modem is short for "Modulator-Demodulator." It is a hardware component that allows a computer or

another device, such as a router or switch, to connect to the Internet. It converts or "modulates" an analog
signal from a telephone or cable wire to digital data (1s and 0s) that a computer can recognize. Similarly,
it converts digital data from a computer or other device into an analog signal that can be sent over
standard telephone lines.

The sole purpose of the modem is to provide you with internet access. If you were to only have one
internet-connected device with an Ethernet port (such as a desktop computer), you could connect the
modem directly to your computer with no need for a router.

Causes of Modem Not Connecting to Internet

There could be several reasons why you can't connect to the internet, but here are some common
issues relating to the modem:

 Loose power or coax connections

 Damaged Ethernet cable connections
 Miscommunication with the router
 Overheating
 Outdated firmware or equipment

How to Fix a Modem That Won't Connect to the Internet

Try these fixes in order, checking along the way to see if the problem is solved before moving on
to the next step.

1. Check the lights on your modem. The lights on the side of your modem can tell you
whether or not your modem is connected to your router and the internet. If none of the
lights on your modem are glowing, then your modem isn't turn on, so you should check
the power cable.
2. Check the power supply and coax cables. Examine all of the cables on your modem to
make sure there are no loose or frayed connections. If the lights on the modem flicker
when you move the power cable, it's probably time for a new power adapter. Likewise, if
the connection pin for the coax cable (the large, round cable that connects to the wall) is
bent, you need to replace it.
3. Reboot your router and modem. Refreshing the device can clear out temporary technical
hiccups that inevitably happen from time to time. If you're going to reboot the modem,
you should reboot the router as well.

Rebooting is different than resetting. Rebooting just shuts down the modem and turns it
back on.
 4. Check your Ethernet cables. An Ethernet cable connects your modem and router. If you
have a spare, switch them out to make sure there's not a problem with the physical
connection.
5. Disconnect all connected devices. If you have many devices connected to your network
(smart home devices, multiple computers, etc.), your modem could be overwhelmed.
Disconnect all devices, reboot the modem, then reconnect your devices. If the internet
starts working but then stops at a certain point, the modem might be at its limit, so you
should talk to your ISP about an upgrade.
6. Plug your computer into your modem. If your PC has an Ethernet port, you can directly
connect it to the modem. If you can use the internet, then the modem is fine, and the
problem lies with your device or router.
7. Keep your modem cool. If your modem keeps resetting, it could be overheating. Keep it 6
inches away from other devices, and make sure the air vents are clear of dust. Don't keep
it near a heater or in a humid environment.
8. Update your modem and router's firmware. Your ISP usually handles software upgrades
for your modem, but if you use a router-modem combo, check for router firmware
updates to ensure you have the latest security patches and bug fixes.
9. Change the Wi-Fi channel. If you have a router/modem combo unit, it could be assigning
too many devices to one Wi-Fi channel. If possible, manually divide your devices
between the two channels, choosing the best wireless channel for each device (not all
devices can connect to 5 GHz).
10. Reset your router/modem to default settings. Look for a small hole on your modem's
underside and use a straightened paperclip to press the small reset button inside.
Restoring the router to its factory defaults will clear any problems with your router's
settings, but it will also remove all passwords, custom DNS settings, and firewalls you've
configured.
11. Contact your internet service provider (ISP). Your ISP can tell you if there's an outage in
your area and check for problems on their end. If they can't resolve the issue, they can
point you in the right direction.
12. Buy a new modem. If you're not renting a modem from your ISP, the modem you're
using might not support the latest wireless standards. Or, you could have more devices
connected than your modem can handle. Check with your ISP for the recommended
modem specs for your internet plan.

COMPUTER VIRUS

A computer virus is a malicious piece of computer code designed to spread from device to
device. A subset of malware, these self-copying threats are usually designed to damage a device
or steal data.

Think of a biological virus – the kind that makes you sick. It’s persistently nasty, keeps you from
functioning normally, and often requires something powerful to get rid of it. A computer virus is
very similar. Designed to replicate relentlessly, computer viruses infect your programs and files,
alter the way your computer operates or stop it from working altogether.
What are the symptoms of a computer virus?
Your computer may be infected if you recognize any of these malware symptoms:

 Slow computer performance

 Erratic computer behavior
 Unexplained data loss
 Frequent computer crashes

How are computer viruses removed?

Antiviruses have made great progress in being able to identify and prevent the spread of
computer viruses. When a device does become infected, though, installing an antivirus solution
is still your best bet for removing it. Once installed, most software will conduct a “scan” for the
malicious program. Once located, the antivirus will present options for its removal. If this is not
something that can be done automatically, some security vendors offer a technician’s assistance
in removing the virus free of charge.

Examples of computer viruses

In 2013, the botnet virus Gameover ZueS was discovered to use peer-to-peer downloading sites
to distribute ransomware and commit banking fraud. While tens of thousands of computer
viruses still roam the internet, they have diversified their methods and are now joined by several
malware variants like:

 Worms - A worm is a type of virus that, unlike traditional viruses, usually does not
require the action of a user to spread from device to device.
 Trojans - As in the myth, a Trojan is a virus that hides within a legitimate-seeming
program to spread itself across networks or devices.
 Ransomware - Ransomware is a type of malware that encrypts a user’s files and demands
a ransom for its return. Ransomware can be, but isn’t necessarily, spread through
computer viruses.

Computer virus protection

When you arm yourself with information and resources, you’re wiser about computer security
threats and less vulnerable to threat tactics. Take these steps to safeguard your PC with the best
computer virus protection:

 Use antivirus protection and a firewall

 Get antispyware software
 Always keep your antivirus protection and antispyware software up-to-date
 Update your operating system regularly
 Increase your browser security settings
  Avoid questionable Websites
 Only download software from sites you trust.
 Carefully evaluate free software and file-sharing applications before downloading them.
 Don't open messages from unknown senders
 Immediately delete messages you suspect to be spam

An unprotected computer is like an open door for computer viruses. Firewalls monitor Internet
traffic in and out of your computer and hide your PC from online scammers looking for easy
targets. Products like Webroot Internet Security Complete and Webroot Antivirus provide
complete protection from the two most dangerous threats on the Internet – spyware and computer
viruses. They prevent viruses from entering your computer, stand guard at every possible
entrance of your computer and fend off any computer virus that tries to open, even the most
damaging and devious strains.

While free antivirus downloads are available, they just can't offer the computer virus help you
need to keep up with the continuous onslaught of new strains. Previously undetected forms
of polymorphic malware can often do the most damage, so it’s critical to have up-to-the-minute,
guaranteed antivirus protection.

A computer network is a system in which multiple computers are connected to each other to
share information and resources.

Characteristics of a Computer Network

 Share resources from one computer to another.
 Create files and store them in one computer, access those files from the other computer(s)
connected over the network.
 Connect a printer, scanner, or a fax machine to one computer within the network and let
other computers of the network use the machines available over the network.

Following is the list of hardware's required to set up a computer network.

 Network Cables
 Distributors
 Routers
 Internal Network Cards
 External Network Cards

TERMINOLOGIES
Device driver is a program that enables a computer and a device to communicate with each other.
Computer operating systems usually come with 'pre-installed' device drivers for the current models
of the popular devices

Device Manager is a Control Panel applet in Microsoft Windows operating systems. It allows
users to view and control the hardware attached to the computer. When a piece of hardware is not
working, the affected hardware is highlighted for the user to deal with. The list of hardware can be
sorted by various criteria.

A task manager is a system monitor program used to provide information about

the processes and programs running on a computer, as well as the general status of the
computer. Some implementations can also be used to terminate processes and programs, as
well as change the processes priority. Task managers can display currently running services
(processes) as well as those that were stopped.