Continued Shut Downs

[Kevin]

I have a 2yr old Toshiba Satellite 2455-S305. I have put a lot of mileage on it, but it is still in pretty good shape. I recently had a hard drive crash and had it replaced.

For about the last 3 weeks and occasionally before that, the computer just totally shuts down about once a night. Usually, it is while I have flopped full and someone is betting into me. Yesterday, it did this twice.

Is this a fan/overheating issue?

Any reco's would be helpful.

Thanks,
Kevin