Originally Posted by TriggerFinger
have you checked the temps? use SpeedFan or similar to check on the temps. observe and note the temp how high it can go or until the laptop shuts off. another way is feel the vents if it is giving out hot air. warm air is normal. if it does, give it a good clean. use a can of air and shoot some thru the vents and heatsink to remove dust and any obstruction.
while using the laptop, be conscious that you do not by accident cover the vents with anything.
I had the same problem with my Toshiba laptop after increasing the RAM to 2 GB. The machine ran very hot and would shutdown. I bought a coolpad and I leave my laptop sitting on the coolpad with its extra fans and have not had a problem since.