reply to ShockWave77
Re: [motherboard] New Build & Random Shutdowns -- Power Supply? I've had bad experiences with Auto voltage settings on Asus boards when tinkering with CPU speeds. Glad to see you got that resolved .
From a quick search, I found a MS knowledge base article on that issue. The last update for it was in August 2010. Assuming you're using Windows 7, is it updated to SP1?
Another thing to try is to change how the power button reacts in Windows. It should be in the Control Panel, Hardware and Sound, Power Options. Set it to do nothing when pressed.