the motherboard might be bad. the CPU might be overheating. the power supply might be bad. the RAM might be bad. there are still many possible problems. you will have to start swapping hardware to find out.
Herb....
My computer has been freezing up at random times (and I'm forced to hit resest or power off, since it won't take any input). It will do this while booting, before posting, or while Windows is running. It tends to freeze up more frequently when running programs that hog processor time.
I have a 1 year old PC-Clone running XP. All my drivers are up to date, and I just re-formated the hard drive and re-installed windows. I've tried using a different BIOS. I've even removed every card/peripheal except the video card. Nothing seems to work. I took it in to a shop and they said they didn't see anything wrong. Any ideas?

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