My PC (P4 3.8Ghz) shuts down constantly, most recently during boot. I checked the BIOS and saw in the PC HEALTH that my CPU is running at 109C - The weird thing is, I KNOW this temp isn't correct, since I just powered it up after leaving it overnight. The room temp is 19C, so I know its impossible to be 109C at the first boot.

Does anybody have any advice for me. I don't think the CPU chip has any damage to it - when the PC runs, it runs fine, until it shuts down again of course. I think that maybe the temp sensor might be broken or something, giving an incorrect reading and therefore shutting down. Is there a way to disable the temp sensor, or do I have another problem that i don't know about?

I would be greatful for any help! Thanks in advance.

If the CPU's fan is not spinning (or totally covered with dust), the CPU can heat up almost instantly. The first thing you need to do is make sure the fan is spinning and the interior is clean of heat trapping dust and dirt.

The fan is running and the CPU chip is free of dust. But I'm almost sure it has to be the CPU chip - I'll get some thirmal gel and replace the chip with another one I have and see what the result is. It's just a bummer because the processing of the chip is fine, it's just that it keeps shutting down.

See my canned text on http://www.d-a-l.com/help/general-ha...-material.html.
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I always like to make sure I have good power before I declare any other hardware bad. Note that lots of things can cause it to shut down besides the CPU. The PSU, bad RAM, or failing motherboard. Could be bad graphics too.

You asked earlier about disabling the sensor, you should be able to do that in the BIOS, but of course, that brings on more risks if it really is heating up.