[Jeff]

Might want to be careful placing the laptop on a towel while it is running. I had a several month old Dell laptop recently die on me after placing it on the carpet overnight (with the lid shut, but still running). Turned out that the air intake is underneath and placing on a bed or carpet causes major overheating with the Dells (lots of Goggle hits of similar things hapenning to many people).

Fix for the Dell was to replace the motherboard and memory (got this done under warranty ... luckily). Suspect yours could be shutting down due to heat issues (inbuilt protection in the BIOS). Might we worth installing a "monitor" program from the manf site or Download.com to see what's hapenning with fan speeds and CPU temperature.

Good Luck,
Jeff