But how about the cheapest part I know of? That CMOS battery could be too low and stop booting.
This part and its effect varies with each PC but it's so cheap at under 1USD that I have to ask if you tested or replaced it.
I purchased a NetVista model# 6269 E2U a couple of months ago, it has a 600mhz Celeron processor and 512mb of ram, a 6.4gb hard drive and windows 98se. I was able to get it up and running with a few fixes and started to play a few games, it played for about an hour then froze, no response from the mouse or keyboard so I rebooted the machine and started to play my games again, about 20 minutes later it froze again so I rebooted again, this went on about 3 more times so I shut it down and removed the cover looking for a cause. Over the last couple of months I have replaced the hard drive, changed the processor, used a substitute power supply and replaced a few of the electrolytic caps. on the motherboard. Can anyone give me any more ideas on the possible problem other than a bad chip. Thanks.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic