Any luck Jen?
I had major problems with my PC couple of months ago - kept freezing, shutting down, blue screens

etc .... tried many things ... ended up being some well hidden trojans deep in my system. Ran all my virus scans, and finally bought Spydoctor - ran a deep scan and voila - a little nasty lurking ....... all OK one the nasty was eliminated ........ huge relief.
May or maynot be your problem