No spyware or viruses detected after several scans over the past couple of days.
My theory is that it's happening roughly ten minutes after I start my music program, Finale. Then *poof* the computer completely shuts off, and then restarts. There's no screen saying Windows is now restarting or anything. Just goes black, a click, and then it starts again.
I've tried reinstalling Finale, still happens - if that actually even has anything to do with it, it may not, I'm not going to bother to keep testing this theory out at the moment.
And when it does happen, it's not like I'm running uber amounts of things at once and my computer just crashes. At the most all I've had open is IE7 or Firefox, utorrent, Finale, and Winamp.