Laptop shutsdown while running

[zinxlinx]

I have IBM T20 Thinkpad PIII 700MHz which shutsdown without notice when I run any processors intensive programs like real player, Windows Media player , Matlab or some times even Acrobat.
I have no clue whats happening. I tried changing the settings in the Boot Menu, nothing works.
Tried using Win 2000 and Win XP.. no use.
Someone suggested it might be problem with the heat sink or overheating..
Help needed immediately.
Thanks in advance.
-Zin

 

[Bug]

Do you even hear the fan kick in when you open those processor-intensive apps? If not, your fan could be dead.
Another thing to check is in your BIOS, if there's anything that dictates what the computer will do when the cpu reaches excessive heat levels.

 

[merlocka]

I have an HP pavillion which does the same deed. I cannot run any distributed computing apps on it or it will shut down in ~10 minutes.

No BIOS options on this could be found.