About a month ago, I began having problems with my computer rebooting. It was as if someone had just hit the reset button. This doesn't appear to be an overheating problem, because it happens anywhere from 3 minutes after I get booted up, to more than an hour before it happens. I installed a new power supply, and this did not help. i thought I might have a virus, but have run 4 different virii checkers and found nothing. To date, I have replaced all but the floppy drive and the CPU chip, an AMD Athlon 1200MHz, and the CD-RW drive. There is another computer plugged in on the same circuit, so I am doubtful of line voltage problems. Can a faulty CPU chip cause this rebooting?