Ok, I believe this should be the right thread... I was tying a word document and the system just shut down without warning. The system will not load POST. When I power it on it just show a blank screen. I got a replacement motherboard and did not help. I also tired a different motherboard and that also did nothing. I did everything the tech support said. Cleared the motherboard CMOS by moving the jumper. I removed and RAM and tired a different video card and that did not work either. It powers on fine and the hard disks and fans spin. I tired a different monitor, both DVI and VGA and that was not the problem. I also tired it with the motherboard outside of the case and different hard drives with no avail. No detectable burning or power surges. The system was not over-clocked and the temperature at idle was around 33 C. BioStar TForce 4 SLI motherboard 1 gig stick ULTRA RAM x2 Cyberlink 420 Watt PSU Windows XP SP2 nVidia GeForce 4 6600 In addition I also tried a Abit KN8 SLI motherboard and a unknown brand PCI video card. Thanks for anyone with sudgestions.