I have one of these circa 2004 laptops and recently it started overheating an shutting down. Mostly this just meant the kids had to move over to Linux (Windows kept doing virus scans) and not play flash games. I finally got around to looking into this the result was dust!

It was actually very easy to fix only five screws to take out and nothing to take apart.

Three screws out and remove the cover:

Then two more screws and the fan lifts out no need to disconnect it.

I got this piece of dust out:

This was left on the filter:

After I cleaned this out the laptop is back to normal and hasn’t shut-down since