Thermal paste for laptop fan

Can you hear the fan?

Does it get hot at the bottom of the laptop?

Yes the bottom of the laptop is always very hot and the fan has been making loud noises since soon after I bought it in Spring 2009. It's been switching itself off for about 3 weeks now and isn't particularly noisy at the moment. It lasts about 5 minutes when switching on normally and about 10 minutes in safe mode. I've managed to retrieve my work from it and put it on an external hard drive so it is backed up. Any advice would be gratefully received.