Only to be sure, run an on-line scan:
http://housecall.trendmicro.com/
Spyware\ad aware\parasites can do "strange" things - did you run the tools mentioned here??
http://reviews.cnet.com/5208-6132-0.html?forumID=32&threadID=1313&start=0
Hardware problem or infection?
My notebook all of a sudden has the fan running all the time amd the display is quite dim. I can still access my programs and everything seems to work normal but sometimes suddenly it shuts down. It can be in 5 minutes or 2 hours; does it look like a hardware or infection problem? Please help. Thanks.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic