TYPES OF COMPUTER SYSTEM
COMPUTER HARDWARE AND SERVICING
LESSON 2, MODULE 4
MA. RACHEL B. ESPINO
Buhatan National High School
• There are several errors in a computer from the
point you open it up to the point you reach the
stand by window (reaching standby windows
means boot process has no error). Here's a list of
1. No Video Output - When you open your PC,
nothing shows up in your monitor and the LED
indicator of your monitor is flashing in yellow
2. No Video Output - Same as number one but
now the LED indicator of your monitor is in steady
3. Doesn't Boot - When you open your PC it will
show the processor brand and/or the
motherboard brand but doesn't continue. Usually
this error will result to system restart over and
4. Never Ending Loading of Operating System -
The computer opens up then boots but when the
operating system loads it doesn't continue and it
will take a lifetime if you're going to wait for it to
5. Lots of pop up windows showing on standby
mode - This also happens even if you try
disconnecting your computer set from the
internet. This is what we called aftershock virus
which will continue to run even if internet is
6. Lots of hardware installation windows appear
- This happens even if you try installing the
hardware. When you restart your set it will
7. Safe mode doesn't work - When you try going
to safe mode all you will see is a list of files in
Command prompt style.
8. Keyboard and mouse system restart - This will
happen only in standby mode, when you move
your mouse or type something, your system will
automatically restart and the worst part is it will
delete a file at random.
9. Sound on/off error - Upon loading the
operating system, you will hear a loading sound
and then the sound stops, when you try running
an audio file, no sound will be heard.
10. Application causes system to restart - Just
like the mouse problem, when you open a
program that will take the whole screen like for
example a game and/or a program applications,
after you close it, it will cause your system to
Operating System Errors
• Aside from the common computer errors,
computers also can have different Operating
System (OS) errors. OS errors can be classified
into various categories, such as:
1. System errors – These are moderately
dangerous types of errors among those that can
pop up on your PC. System errors are caused by
malfunctioning hardware components, corrupted
operating system modules, etc.
2. Runtime errors – Runtime errors are caused by
corrupted or malfunctioning system files or
software executables. Most runtime errors cause
the application that caused it to shut down.
However, more serious runtime errors may cause
the system to become unstable or unresponsive,
leaving you with no choice but to reach for the
3. Stop errors – Stop errors are caused by
corrupted hardware, especially malfunctioning
RAM modules and bad sectors on hard disks. Stop
errors can be difficult to resolve at times.
4. Device Manager Errors – These are usually
caused by corrupted driver files or malfunctioning
hardware components. In case of the former
cause, the problem is usually solved simply by
reinstalling or updating the drivers. However, the
latter cause can often be solved only by replacing
5. POST code errors – POST code errors are
caused by malfunctioning hardware components,
and are characterized by short beep sounds from
the tiny internal speaker of your motherboard.
POST code errors occur when you press the power
button to turn on your PC..
6. Application errors – These can be caused at
any point of time. As the name suggests, these
are caused by applications while those are
running. These are usually caused by glitches in
the program code itself. These are usually
resolved by updating the program to its latest
7. Browser Status Codes – These are caused by
problems faced by browsers when trying to access
a website. These can be caused by misplaced web
pages in the server of the website itself, or due
to connection problems. For instance, a 404 error
would indicate that the browser is trying to
access a webpage that does not exist in the
• Probably the most frustrating problem computer
users run into are startup problems, where your
computer won’t boot. Equally annoying are error
messages you constantly run into during your
computer’s startup process. In this module you
will be given a few tips on how you can avoid
some of the most common problems that
happen right after your computer is turned on.
• Here you will learn the basic troubleshooting.
Trial and error:
• When you find a faulty component in your
computer, check it with the other computers so
that you can make sure whether the fault is in
the component or not.
• In case of any device failure, check all the cables
of your computer such as data cables, power
cable, internal circuitry cables and make sure
that all these are plugged in and working fine.
• : Check the hardware settings in the CMOS and
in the device manager of the system and make
all the device drivers up to date and all the cards
are plugged in properly.
• When you notice a software or hardware error in
your computer, determine what was changed
before the problem occurred.
• In the event viewer, you will find the error or
warning messages associated with any faulty
hardware or software.
• Troubleshooting is a big learning option and we
can learn a lot when we face any kind of
troubleshooting in our computer. Make notes
including the error messages and their solutions,
so that you have a record on how a certain
problem occurred and how did you solve it.
1. Check the POST
• POST stands for Power On Self-Test. This is
generally the first or second thing that appears
on a computer after turning on the power. This
appears before the operating system begins to
load. The POST will display any problems found
with hardware that makes the computer unable
to boot, POST may also display problems with
hardware that allow the computer to boot, but
not operate at its full capacity during operation.
2. Notice the load time of the OS
• 2. Notice the load time of the OS (operating
system). A longer than usual load time may
indicate errors in the hard drive.
3. Notice any graphics problems once
the OS has loaded
• Reduced graphics may indicate driver failures or
hardware failures with graphic cards.
4. Perform an auditory test
• An auditory test is an unorthodox, but still effective way
of judging how a computer is working. With the
computer on and running, play any decent length audio
file (usually above 30 sec). If the audio is choppy or slow,
it usually means that the processor is working at an
elevated level, or there is not enough RAM to run all
programs loading. Changing the startup sound is a great
way to apply this test. Another issue associated with
choppy sounds is PIO (Programmed Input/Output)
Mode. This affects how the hard drive reads and writes
data from a drive. Switching to Direct Memory Access
(DMA) allows for faster reads and writes, and can
sometimes repair choppy audio.
5. Check any newly installed hardware
• Many operating systems, especially Windows,
can conflict with new drivers. The driver may be
badly written, or it may conflict with another
process. Windows will usually notify you about
devices that are causing a problem, or have a
problem. To check this use the Device Manager,
this can be accessed by entering the Control
Panel, clicking the System icon, clicking the
Hardware tab, and clicking on Device
Manager. Use this to check and arrange the
properties of hardware.
6. Check any newly installed software
• Software may require more resources than the
system can provide. Chances are that if a
problem begins after software starts, the
software is causing it. If the problem appears
directly upon startup, it may be caused by
software that starts automatically on boot.
7. Check RAM and CPU consumption
• A common problem is a choppy or sluggish
system. If a system is choppy it is good practice
to see if a program is consuming more resources
than the computer can provide. An easy way to
check this is to use the Task Manager, right click
on the taskbar select Task Manager, and click
the Processes tab. The CPU column contains a
number that indicates the percentage of CPU the
process is consuming. The Memory Usage
column indicates how much memory a process is
8. Listen to the computer, if the hard
drive is scratching or making loud
noises, shut off the computer and have
a professional diagnose the hard drive
• Listen to the CPU fan, this comes on a high
speed when the CPU is working hard, and can
tell you when the computer is working beyond
9. Run a virus and malware scan
• Performance problems can be caused by
malware on the computer. Running a virus scan
can unearth any problems. Use a commonly
updated virus scanner (such as Norton Antivirus
or Avast! Antivirus)
10. Check for the problem in safe
• To enter safe mode, tap F8 repeatedly during
POST (this works on most systems). If the
problem persists in safe mode, it is a fair bet that
the operating system itself is to blame.
• 1. Double check the power connections.
• 2. Voltage Regulator and power supply could
• cause power failure in the computer unit.
• 3. Check the power cords and cable connectors
• in your computer unit.
• 4. Unseated card. Loose cards could cause
• 5. Check the boot sequence configuration in the
advance BIOS (Basic Input /Output Unit) setup.
• Things to look for if a PC is connected to the
internet or network:
• First check the cable connecting to the
network card into the network hub.
• Check the back of the computer to see if
the network card light is on
• Check the network cable ( use cable
• Check the network HUB
IDENTIFY THE FOLLOWING ERRORS
1. Moderately dangerous types of errors among those that
can pop up on your PC.
2. Caused by malfunctioning hardware components, and are
characterized by short beep sounds from the tiny internal
speaker of your motherboard.
3. Caused at any point of time. As the name suggests, these
are caused by applications while those are running.
4. Usually caused by corrupted driver files or malfunctioning
5. Caused by corrupted or malfunctioning system files or
6. Caused by corrupted hardware, especially malfunctioning
RAM modules and bad sectors on hard disks.
7. Caused by problems faced by browsers when trying to
access a website.