REASONS WHY COMPUTERS CRASH YOU MUST KNOW
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
Microsoft 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 ( www.nai.com). Another is Norton AntiVirus 2000, made by
Symantec ( www.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
www.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.
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.
