CPT Furious, I had similar problems with my own laptop when I first acquired it--maybe my experience can help you out.
I inherited a Dell laptop (an Inspiron 5100) that is a model that has heat-related issues that cause lockups and sudden shut downs. These problems are mainly attributed to the combination of dust buildup and heavy processor utilization, and can be alleviated by a thorough cleaning with compressed air and elimination of spyware on the computer.
The Easy part: Get a can of compressed air from your local Radio Shack or office supply store and clean the ventilation ports on your laptop (turned off, of course). Use liberally; continue to clean it out until you have sneezed at least six times.
Less Easy part: The more the cpu is used, the more heat it generates. On your computer, boot it fresh, allow it to fully load windows and click on Start --> Run..., type in taskmgr and click ok. This will bring up the Windows Task Manager, where you can find info on the programs and the processes that are running on your computer.
Click on the Processes tab in the Windows Task Manager window and click the CPU column heading--this will let you see which processes are using the most CPU time. Also note the number of processes you have running; a count of processes and cpu usage are both given at the bottom of the window.
On a fresh install of windows, with no open programs, the number of processes will vary by computer configuration, but in my experience anywhere from 30-45 is pretty normal. Mine right now is at 38. Watch your CPU usage there at the bottom for a few seconds. If it stays above 10% when you're not doing anything, and no programs you know of are running, you mave have an issue with spyware, viruses, or a windows/software/driver issue.
Spyware often causes high cpu utilization, which can definitely cause overheating issues. If your CPU usage remains high I'd recommend you first ensure you have all the correct drivers for your hardware, and if so, I'd try running a spyware detection program.
Download and install a spyware checking program--I usually recommend
Ad-Aware and
Spybot: Search and Destroy because they are effective, constantly updated, and FREE. Install and run the programs and see if they locate any problems. If so, follow each program's prompts to remove or quarantine the offenders.
Try these if you can, and report back to us on how everything works out. I know how frustrating computer issues can be; I've worked as a computer tech (professionally and as the family pc doc) for years.