Thanks to both of you for your quick reply!
Ok, after a bit of research (wanted to make sure exactly what a "heat sink" looks like!), I was able to remove and clean the heat sink & fan. That is the same fan I usually clean out every month or two with cotton swabs. There was not a whole lot of dust on the blades or cpu or the fan, just a very light layer; I'm not sure if the lack of heavy dust build up changes anything?
I used cotton swabs & a small air compressor, cleaning out all the vents and the whole interior. I used rubbing alcohol to clean the thermal paste off.
Also, I did not have thermal paste so I replaced without it, having read that some use it, some don't.
After restarting the computer, the first thing that happened was Windows began loading and I had stripes of colorful horizontal lines across the screen. I took a picture with my cell phone. Before, the screen would be all black with about an inch or two on top being streaks of colorful lines just like in this image.
So I did a hard boot, and this time Windows loaded fine. But once the desktop appeared, it froze.
I re-booted again, and this time everything seemed fine and it's still on half hour later.
I installed SpeedFan last week and noticed the temp of the GPU yesterday was around 58-60, if I remember correctly. (I didn't think to check all that today before cleaning the heat sink/fan). Now the temps are a bit cooler, GPU about 50 and each of the two Cores mid 40s (they were around 34 on startup).
Also, since our computer takes several minutes to load completely, I did some research & was able to use MSCONFIG to remove quite a few programs from Startup.
We still have to test further to see if the issue is resolved, but my concern is that first screen on turning the computer on after cleaning.
Editing to add a screenshot of HWMonitor (thx for the tip on that program!)
Edited by JadedGem, 29 September 2010 - 08:31 PM.