BB –
I’m not aware of a problem with XP SP2 causing over heating. If you have a link to this information I would appreciate it.
That being said, how old is your computer, has it had any problem lately, what brand is it…
I have seen overheating caused by various problems. Bad CPU (though this is usually noticeable right away), excessive external heat (I presume it’s still cold weather in your area, so the only thing that would likely cause this sort of problem is being located near a heater), drying-out of the silicone gel on the CPU (which would be caused by any of the above two situations), or even plain dust getting into your computer and clogging the fan.
Or else – some sort of electrical problem either internal or external which is preventing the mainboard from properly detecting fan speed and CPU heat. Another possibility is that the mainboard itself is beginning to fail.