Dusting out the vents and heatsinks?
How old is this machine and do you keep all spyware off it?
PS. See -> http://www.informationweek.com/story/showArticle.jhtml?articleID=60300177&pgno=4
I own a Compaq presario 2500.
Recently its been turning itself off when Ive been using certain programs (burning CD's, using media player etc). It happened twice yesterday for no apparent reason. It also seems to be heating up pretty bad but not sure if thats normal or not.