Out of curiosity, how old is the laptop? If it's more than about 6 months old (AND it didn't overheat when you first got it), you need to clean the fans (and probably the heatsink). Most laptops have access panels on the bottom that you can open up to get to the fan(s). Just open these panels, give the insides a good general dusting with an air duster, and then spray directly into the ventilation grilles to try to dislodge some more of the built-up gunk. You'd be amazed how much dust can build up in a laptop.
As a phone support technician, I always tell my customers that once every three months is a pretty good time-frame for cleaning their notebooks, and once a year is the absolute longest they should even think of going. So, if it's been a while since you bought/cleaned the system, give it a shot. You might just find the jet engine quieting down