Thanks for your help. I'm an old geek, and have spent weeks checking everything. CPU temp is fine, heatsink is fine. I've run 'sandra' and AIDA32, memory testers - nothing shows up. I've taken everything out, cleaned the contacts, checked the board for corrosion, and more. I've been to every Tech Forum I can think of. This same problem shows up on All Windows OS' and Solaris, FreeBSD and Linux. All my video drivers are correct for my OS. The safe-mode loop is well documented over at ViaArena, and Microsoft confirms it. But no fix has been found. Same with this reboot problem. I read that gamers are having this problem when Open GL is active. It could be OpenGL and Direct X... I'll keep working on it. Thanks for taking the time to help - it is appreciated.