Get a temperature monitoring program and check all the temps. Possible that the CPU cooler is improperly connected or heat transfer paste needs to be replaced.
I have a computer given to me that was built by a friend. It's a Dell 8200 case and Dell motherboard. The hard drive went out and I installed a new one and installed XP Pro. The computer hasn't worked right since. I ran some test with different utilites and all of them indicate the processor is working way below speed. i.e. expected speed, 2800Mhz, actual speed, .50 Ghz. FSB expected speed, 533Mhz, actual speed 97 Mhz. Also when I turn the computer on and hit F2 and look at the event log in start up there is a mile long log of "CPU overheating". Any ideas? The fan is working and is unclogged. Thanks for any ideas.

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