5Reasons WhyPCCrash

5 Reasons Why PC
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.