Hey don't suppose your laptop is a Multivision is it??
I had a similar problem with my now deceased laptop

. For me, mine mainly overheated when playing games but soon progressed onto overheating for a lot of things.
From what I can tell, your laptop sounds pretty toasty and the more it overheats, the more it will get damaged. Sometimes with laptops things just go wrong for no reason (imo most are only good for ~3 years before things start to go wrong).
The main advice I can give is if your laptop is a reputable make e.g. Dell. HP, etc. contact them about it or post on their user forums, there are tons of people who will know exactly what is wrong.
Either that or buy a cooling mat which I did, only cost about £25 and kept it nice and cool (although in the end my HD just failed

).
Cooling Mat:
http://www.expansys.com/product.asp?code=123482&partner=froogle