BSOD with Driver IRQL Not Less or Equal

I sometimes get the BSOD with some message like:

Driver IRQL Not Less or Equal

What does this mean and how do I fix it? Is it hardware or software related problem?

It sound to me that your RAM has gone bad.

I suggest you download memtest 86+ and run all the mem tests, if you see any errors then one of your RAM sticks is failing.

This is a known issue related to RAM.

Quite common and can be hard to pin point. Frequently a driver related problem (suspect any non WHQL drivers or non XP compatible), sometimes it can also be caused by security software not "playing nice".

I would say try booting in safe mode and reinstalling the video drivers.

Try this:

1. Click on start - run and in the run(search in Vista) box type in devmgmt.msc.
2. In the device manager click on the menu view and click on "show hidden devices".
3. Now in the task manager list look for "Non Plug n Play drivers" and expland it.
4. Under non plug n play drivers look for KmxCF and double click on it and and in the KmxCF properties window click on the tab driver and change the startup type to "demand"
5. repeat the step 4 for KmxFw and close the device manager and restart your computer.

Hope this helps.

Try to go to Control Panel > Administrative Tools > Event Viewer to see a log of the fault. There should be a log of the crash there and what caused it. Generally, the IRQL error message could indicate memory issues.