I don't know if this will help but I was having similiar problems with Vista Ultimate 64-bit crashing at least once a day. Sometimes overnight when it wasn't even doing anything (that I know of). I reinstalled most every driver trying to fix the problem. I finally did one thing I hadn't thought of. I updated the bios. Since then I have not had one BSOD, no glitches, nothing. Smooth as silk. Give it a try, if you haven't already.