The best i can offer you is a work through list

1. check to make sure no processes are constantly tying up the processor, this is common with certain malware.
2. can you feel any breeze coming from the laptops exhaust vent? if not then it could mean the fan on the heatsink has failed or the laptops cooling vent is blocked, look to see if you can see any dust or fluff obsuring the vent.
3. if the fan appears to be ok if could be the thermal conductive paste between the processor and the heatsink needs to be replaced.

this is just a few ideas – more here http://www.computer-adviser.com/stop-laptop-overheating.html

hope it helps

Sil