:disgust:All of a sudden I've started getting the BSOD. The reason was different many of the times. I have gotten IRQL_NOT_LESS_OR_EQUAL for ntoskrnl.exe, n4_mini.sys, and hal.dll. My PC might run for days without a problem, then the BSOD's hit, and I can hardly get it to run at all. I switched my primary HDD to my old one that has W2K like the first one. Boom, I got the ntoskrnl.exe BSOD. I rebooted, and things were stable until I tried to upgrade W2K to SP4. During the install, I got a BAD_POOL_HEADER BSOD. It didn't point to anything. I'm beginning to think I have a hardware problem, but what is it? RAM, MOBO, HDD, video card? Any ideas?