I have a laptop that runs the OS just fine (fan runs fast though). I can use the computer as long as I want and will have no problems. If I restart it after using it for awhile, it will typically not make it to the XP splash screen before rebooting on its own. If I wait awhile it will power up just fine. However, if I wait awhile (letting the computer cool) I can use the BIOS for awhile or make it through some of the re-installation of XP from disc process but never all of the way. This seems like a heat issue so I replaced the thermal compound on the CPU and the GPU but not the chipset due to it having a thermal pad. Since the computer seems to shut down only when in the BIOS, would this be from the chipset overheating? If so do you just have to get a new thermal pad (I assume putting thermal compound on or cleaning the pad wouldn't help much)?
More information: I forgot to mention that I updated the BIOS to a newer version and also set to factory defaults with no luck. The battery does not work either; it says 100% charged but will turn off instantly if un-plugged. <-Not sure if relevant, does not seem to be a power issue.
Will an overheating chipset cause the computer to shutdown only when running in the BIOS?