Your PC should not max out at this kind of tasks, there is a good chance something is "broken". I have used way older and much weaker computers and they did not show this kind of behaviour.Quote from bronks:
My rig's a Dell/ p4 3.20Ghz with 2 gigs of RAM
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Over the past 6 mos. the CPU has been regularly maxing out 100%, even for run of the mill tasks. Example:
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I've never heard of a processor getting "tired" before, but it sure seems like the case. Do I need to upgrade?
Download CPUID HWmonitor and CPU-Z to check the temperatures and Speeds on your board, maybe the CPU throttles down beacuse a fan has broken etc. there can be a lot of causes.
Run virus tests, tests for trojan horses to exclude this kind of stuff though it does not sound likely. Then run memtest and chkdsk. If all of this does not reveal any cause have it checked by a computer store near by.
Cheaper than buying a new one, and if you decide to buy a new one (don't upgrade) you will have one extra machine.