My MacBook (2 ghz, Core Duo) always seems to be running hot. The fans are pumping as hard as they can and the bottom turns really darn hot to the touch. Usually, I am only running Firefox, iTunes, and Word. Now, I understand that it should run hot when I am, say, using Photoshop, but these three programs arn't that much heavy lifting for my computer. I've tried blowing air through the exhaust fans, but that doesn't seem to do anything other than remove a small amount of dust. I am worried that this overheating is wearing down my battery and I am tired of the fan constantly running. What should I be checking for to see if there is a problem?