Remids me alot of when my OCZ took a poop. Started out as random as you say, them more frequent. In the end I had eliminated everything else, and couldnt get to windowz w/out a instant BSOD! Even if you have a crappy PSU laying around...try it with just enough parts to run see if it boots.
On a side note ABIT mobo are serious power drinkers just to idle, similar to my DFI in that situation as well!