hey guys. i recently instaled Vista on my PC and turned it on the other day, the fans spin and hard drives spin up. but nothing else, no post, it wont even turn off when i hold the power button or beep at me if there is no RAM plugged in. its an ASUS P4S800 mobo. i have taken out the battery to try and clear the cmos but still nothing. im thinking it is a fried mobo, but could it be the PSU? if it is the PSU any ideas on replacements?