Get some heat sink compound then power off, remove the AC cord, get inside the machine, pull the CPU heatsink off, wipe the old compound off with a paper towel, apply fresh compound, put the CPU heatsink back on and button it up. That stuff does dry out.
Bob
I have had a Dell XPS 400 for the past 5 years. Up until a month ago I ran fantastical. Well I was going through some old programs I dont use and removed the oldest version of Java. I also may have deleted the "prefetch" folders files.
Since then I have had this problem. I will turn on the computer, log on, and open some thing. During this time it run slower than it used to. Then everything just locksup. The cpu usage either drops to 0 or freezes on the last reading. When I dont have Task manager open it wont open, It wont shut down, and it doesnt start responding again.
It is cleaned out from dust and feels cool in side. Also it seems to lockup faster when on the internet. (tried: firefox, chrome, IE7)
Any ideas. Sorry for the long post.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic