is the laptop on warranty? If so talk to the people you got it from and dont open it cause youll void the warranty. If its not on warranty, just pop it open and have a look. there might be a build up of dust on it that you can easily clean off. Or you could get a replacement fan for it and put it on yourself (not much effort involved there)
i got a thinkpad ibm a20m got it in 2001. i heard these friggin things were top of the line...well, at least at the time, but this crap is just too loud
thanx