10 Reasons Why PCs Crash

10 Reasons Why PCs Crash

Fatal error: the system has become unstable or is busy," it says.
"Enter to return to Windows or press Control-Alt-Delete to restart
your computer. If you do this you will lose any unsaved information in
all open applications."

You have just been struck by the Blue Screen of Death. Anyone who uses
Mcft Windows will be familiar with this. What can you do? More
importantly, how can you prevent it happening?

1 Hardware conflict

The number one reason why Windows crashes is hardware conflict. Each
hardware device communicates to other devices through an interrupt
request channel (IRQ). These are supposed to be unique for each
device.

For example, a printer usually connects internally on IRQ 7. The
keyboard usually uses IRQ 1 and the floppy disk drive IRQ 6. Each
device will try to hog a single IRQ for itself.

If there are a lot of devices, or if they are not installed properly,
two of them may end up sharing the same IRQ number. When the user
tries to use both devices at the same time, a crash can happen. The
way to check if your computer has a hardware conflict is through the
following route:

* Start-Settings-Control Panel-System-Device Manager.

Often if a device has a problem a yellow '!' appears next to its
description in the Device Manager. Highlight Computer (in the Device
Manager) and press Properties to see the IRQ numbers used by your
computer. If the IRQ number appears twice, two devices may be using
it.

Sometimes a device might share an IRQ with something described as 'IRQ
holder for PCI steering'. This can be ignored. The best way to fix
this problem is to remove the problem device and reinstall it.

Sometimes you may have to find more recent drivers on the internet to
make the device function properly. A good resource is www.driverguide.com.
If the device is a soundcard, or a modem, it can often be fixed by
moving it to a different slot on the motherboard (be careful about
opening your computer, as you may void the warranty).

When working inside a computer you should switch it off, unplug the
mains lead and touch an unpainted metal surface to discharge any
static electricity.

To be fair to Mcft, the problem with IRQ numbers is not of its making.
It is a legacy problem going back to the first PC designs using the
IBM 8086 chip. Initially there were only eight IRQs. Today there are
16 IRQs in a PC. It is easy to run out of them. There are plans to
increase the number of IRQs in future designs.

2 Bad Ram

Ram (random-access memory) problems might bring on the blue screen of
death with a message saying Fatal Exception Error. A fatal error
indicates a serious hardware problem. Sometimes it may mean a part is
damaged and will need replacing.

But a fatal error caused by Ram might be caused by a mismatch of
chips. For example, mixing 70-nanosecond (70ns) Ram with 60ns Ram will
usually force the computer to run all the Ram at the slower speed.
This will often crash the machine if the Ram is overworked.

One way around this problem is to enter the BIOS settings and increase
the wait state of the Ram. This can make it more stable. Another way
to troubleshoot a suspected Ram problem is to rearrange the Ram chips
on the motherboard, or take some of them out. Then try to repeat the
circumstances that caused the crash. When handling Ram try not to
touch the gold connections, as they can be easily damaged.

Parity error messages also refer to Ram. Modern Ram chips are either
parity (ECC) or non parity (non-ECC). It is best not to mix the two
types, as this can be a cause of trouble.

EMM386 error messages refer to memory problems but may not be
connected to bad Ram. This may be due to free memory problems often
linked to old Dos-based programmes.

3 BIOS settings

Every motherboard is supplied with a range of chipset settings that
are decided in the factory. A common way to access these settings is
to press the F2 or delete button during the first few seconds of a
boot-up.

Once inside the BIOS, great care should be taken. It is a good idea to
write down on a piece of paper all the settings that appear on the
screen. That way, if you change something and the computer becomes
more unstable, you will know what settings to revert to.

A common BIOS error concerns the CAS latency. This refers to the Ram.
Older EDO (extended data out) Ram has a CAS latency of 3. Newer SDRam
has a CAS latency of 2. Setting the wrong figure can cause the Ram to
lock up and freeze the computer's display.

Mcft Windows is better at allocating IRQ numbers than any BIOS. If
possible set the IRQ numbers to Auto in the BIOS. This will allow
Windows to allocate the IRQ numbers (make sure the BIOS setting for
Plug and Play OS is switched to 'yes' to allow Windows to do this.).

4 Hard disk drives

After a few weeks, the information on a hard disk drive starts to
become piecemeal or fragmented. It is a good idea to defragment the
hard disk every week or so, to prevent the disk from causing a screen
freeze. Go to

* Start-Programs-Accessories-
System Tools-Disk Defragmenter

This will start the procedure. You will be unable to write data to the
hard drive (to save it) while the disk is defragmenting, so it is a
good idea to schedule the procedure for a period of inactivity using
the Task Scheduler.

The Task Scheduler should be one of the small icons on the bottom
right of the Windows opening page (the desktop).

Some lockups and screen freezes caused by hard disk problems can be
solved by reducing the read-ahead optimisation. This can be adjusted
by going to

* Start-Settings-Control Panel-System Icon-Performance-File System-
Hard Disk.

Hard disks will slow down and crash if they are too full. Do some
housekeeping on your hard drive every few months and free some space
on it. Open the Windows folder on the C drive and find the Temporary
Internet Files folder. Deleting the contents (not the folder) can free
a lot of space.

Empty the Recycle Bin every week to free more space. Hard disk drives
should be scanned every week for errors or bad sectors. Go to

* Start-Programs-Accessories-System Tools-ScanDisk

Otherwise assign the Task Scheduler to perform this operation at night
when the computer is not in use.

5 Fatal OE exceptions and VXD errors

Fatal OE exception errors and VXD errors are often caused by video
card problems.

These can often be resolved easily by reducing the resolution of the
video display. Go to

* Start-Settings-Control Panel-Display-Settings

Here you should slide the screen area bar to the left. Take a look at
the colour settings on the left of that window. For most desktops,
high colour 16-bit depth is adequate.

If the screen freezes or you experience system lockups it might be due
to the video card. Make sure it does not have a hardware conflict. Go
to

* Start-Settings-Control Panel-System-Device Manager

Here, select the + beside Display Adapter. A line of text describing
your video card should appear. Select it (make it blue) and press
properties. Then select Resources and select each line in the window.
Look for a message that says No Conflicts.

If you have video card hardware conflict, you will see it here. Be
careful at this point and make a note of everything you do in case you
make things worse.

The way to resolve a hardware conflict is to uncheck the Use Automatic
Settings box and hit the Change Settings button. You are searching for
a setting that will display a No Conflicts message.

Another useful way to resolve video problems is to go to

* Start-Settings-Control Panel-System-Performance-Graphics

Here you should move the Hardware Acceleration slider to the left. As
ever, the most common cause of problems relating to graphics cards is
old or faulty drivers (a driver is a small piece of software used by a
computer to communicate with a device).

Look up your video card's manufacturer on the internet and search for
the most recent drivers for it.

6 Viruses

Often the first sign of a virus infection is instability. Some viruses
erase the boot sector of a hard drive, making it impossible to start.
This is why it is a good idea to create a Windows start-up disk. Go
to

* Start-Settings-Control Panel-Add/Remove Programs

Here, look for the Start Up Disk tab. Virus protection requires
constant vigilance.

A virus scanner requires a list of virus signatures in order to be
able to identify viruses. These signatures are stored in a DAT file.
DAT files should be updated weekly from the website of your antivirus
software manufacturer.

An excellent antivirus programme is McAfee VirusScan by Network
Associates ( nai.com). Another is Norton AntiVirus 2000, made by
Symantec ( symantec.com).

7 Printers

The action of sending a document to print creates a bigger file, often
called a postscript file.

Printers have only a small amount of memory, called a buffer. This can
be easily overloaded. Printing a document also uses a considerable
amount of CPU power. This will also slow down the computer's
performance.

If the printer is trying to print unusual characters, these might not
be recognised, and can crash the computer. Sometimes printers will not
recover from a crash because of confusion in the buffer. A good way to
clear the buffer is to unplug the printer for ten seconds. Booting up
from a powerless state, also called a cold boot, will restore the
printer's default settings and you may be able to carry on.

8 Software

A common cause of computer crash is faulty or badly-installed
software. Often the problem can be cured by uninstalling the software
and then reinstalling it. Use Norton Uninstall or Uninstall Shield to
remove an application from your system properly. This will also remove
references to the programme in the System Registry and leaves the way
clear for a completely fresh copy.

The System Registry can be corrupted by old references to obsolete
software that you thought was uninstalled. Use Reg Cleaner by Jouni
Vuorio to clean up the System Registry and remove obsolete entries. It
works on Windows 95, Windows 98, Windows 98 SE (Second Edition),
Windows Millennium Edition (ME), NT4 and Windows 2000.

Read the instructions and use it carefully so you don't do permanent
damage to the Registry. If the Registry is damaged you will have to
reinstall your operating system. Reg Cleaner can be obtained from
jv16.org

Often a Windows problem can be resolved by entering Safe Mode. This
can be done during start-up. When you see the message "Starting
Windows" press F4. This should take you into Safe Mode.

Safe Mode loads a minimum of drivers. It allows you to find and fix
problems that prevent Windows from loading properly.

Sometimes installing Windows is difficult because of unsuitable BIOS
settings. If you keep getting SUWIN error messages (Windows setup)
during the Windows installation, then try entering the BIOS and
disabling the CPU internal cache. Try to disable the Level 2 (L2)
cache if that doesn't work.

Remember to restore all the BIOS settings back to their former
settings following installation.

9 Overheating

Central processing units (CPUs) are usually equipped with fans to keep
them cool. If the fan fails or if the CPU gets old it may start to
overheat and generate a particular kind of error called a kernel
error. This is a common problem in chips that have been overclocked to
operate at higher speeds than they are supposed to.

One remedy is to get a bigger better fan and install it on top of the
CPU. Specialist cooling fans/heatsinks are available from www.computernerd.com
or www.coolit.com

CPU problems can often be fixed by disabling the CPU internal cache in
the BIOS. This will make the machine run more slowly, but it should
also be more stable.

10 Power supply problems

With all the new construction going on around the country the steady
supply of electricity has become disrupted. A power surge or spike can
crash a computer as easily as a power cut.

If this has become a nuisance for you then consider buying a
uninterrupted power supply (UPS). This will give you a clean power
supply when there is electricity, and it will give you a few minutes
to perform a controlled shutdown in case of a power cut.

It is a good investment if your data are critical, because a power cut
will cause any unsaved data to be lost.