From: jase on 10/20/2003
Check to see if you pc 'is' overheating, take of the side panel to your pc and check that the CPU fan is running, watch the fan as your computer boots, does the fan stop running or slow right down?
In your BIOS you should have a 'PC Health status' option, check the temperatures to the CPU here.
Check the fan is not malfunctioning, listen for irregular sounds from the fan, like as if the fan is grinding where there maybe a Bearings issue or bushes issue, usually the CPU fan is quite reliable, and your PC is relatively new so don't suspect the CPU to be the culprit unless you definitely know.
Also check in the BIOS that you have not enabled the CPU fan detection. The system may think that your fan is not running and subsequently shuts down your pc.
If you have recently reset your BIOS to default settings you may have overlooked the setting to the CPU fan detection setting.
Did you build your own PC? If so did you apply thermal compound to your CPU before mounting the Heat sink ?