You've cleaned up its vents and heatsinks?
Hint: Canned air.
My computer is cutting off, mostly during startup, but occasionally in the middle of something. I have ran the utilities... clean up, disc scan, defrag, but nothing seems to help. I use this computer mostly for internet. My ISP is PeoplePC, but I installed AOL to see if it helped and results were about the same. My system info is below. Any help will be appreciated.
Prod Info
Sony Notebook
Model PCG-F270(UC)
Version 01
Bios version Ro202K
OS version 4.10.1998
Windows 98
System Info
CPU Pentium 2
Clock freq 333mhz
Sys mem 128 mb
Cache mem 256 k bytes
HDD Partition 1: 5.84

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic