From: Computerpilot on 06/28/2002
Are you getting error messages? What OS are you running?
If you are not getting error messages but your system just slows to a crawl or stops completely and Control-Alt-Del is completely ineffective (my test is if I cannot change the light for my caps lock by hitting the caps lock key, then you have a complete lockup), then it is entirely possible it could be a hardware issue.
The first thing I would take a look at is the BIOS setting and how you have the clock speed set. Maybe you do not have the jumper settings correct and you are overclocking your processor. This would cause your computer to completely halt. Also, do you have sufficient cooling of your processor? The new XP processors can run mightly hot at times. Make sure that the fan is even spinning. You might have forgotten to connect it back up!
I would check my RAM next. Did you mix and match RAM chips? ECC to non-ECC memory might create this type of problem. Make sure that you have the right memory. Also, some motherboards may support the PC133 and PC100 RAM clock speeds. Make sure you have these settings correct in your BIOS.
After you check these items and you are still having the problem, then you need to do some hardware troubleshooting. Start with the processor upgrade. Then add the RAM then the video card.
Let me know if this helps. Post back if you need some other ideas.