Question : Problem: Toshiba Satellite A70-S249 suddenly powers down

I have a Toshiba Satellite A70-S249 that will suddenly power down after it's been on for just a few minutes - when in Windows or when running Hitachi DFT.  The first thing I think is overheating.  However, the fan is running but it feels pretty hot.  If it is an overheating issue, what are the possible fixes?  Would the MB have to be replaced?  If it's something else, how would I determine that?  Thank you.

Answer : Problem: Toshiba Satellite A70-S249 suddenly powers down

This overheating issue is well known to this model. There is  aguide as it requires disassembly of the laptop to get to the heatsink. You may first attempt to blow through the cooling vents with computer grade compressed air, but if the heatsink is clogged then this guide will how you how.
http://www.irisvista.com/tech/laptops/ToshibaA75/satA75_1.htm