Something is wrong with my laptop, I think it is overheating?

Yesterday I was on my Compaq Presorio R3000 just typing some family history on my Family Tree Maker 2005 in my living room. While I was typing I noticed that my laptop just froze and there was no movement. I thought that it might be overheating since I placed it on a Persian Rug, but I tried turning it on at least 3 times on a wooden, cold surface. Same effect. Then I went on Yahoo Answers and gathered up some information. One guy was saying that Zone Alarm might be the problem (which I had installed on my laptop). Another guy said that he used a computer duster to dust off the dust in the cooling fan. I tried that and didn't work. Then, out of the blue, my Norton Antivirus scanner says it detected and blocked a worm. What is going on with my computer? Is it overheating or is there a worm or virus present on my computer? The last time I went on I checked on Task Manager for the performance and this is what I had before it froze, again:

18% CPU Usage

396 Mb PF usage

Something is wrong with my laptop, I think it is overheating?triumph

Try running it on safe mode for a few hours, having it do something in the background to use CPU power. If it does freeze, then it's your hardware. If it doesn't, most likely there's something messing with the OS.

#### UPDATE ####

From the new data you've supplemented, I can only assume that it's an error in the memory buffer system, which in this case would most likely be RAM. Experiment with that theory for a while.