Windows will run for maybe 5 minutes, then the system will suddenly power off. Sometimes it will happen as the Windows is starting to load. I've been running in safe mode for about 2 hours now with no problems.
I just rebuilt my system after a lightning strike/power surge knocked out my MB and video card. Got new MB through RMA and a bought a new AGP card. Before all that, I took my system into the local, trustworthy computer shop and the tech confirmed my MB and graphics card were fried, but RAM and everything else were fine.
After reassembling the system, the Windows would crash as it was loading, every time. I did a fresh install of windows, took out all the PCI cards, and even tried different HDDs. My configuration is the same as it was before except for the graphics card. Before, I had th original ATI AIW Radeon 4x AGP. Now I'm using an MSI NX6600GT 8x AGP.