T41 freezing, no BSOD action

[Jeff85]

I get some intermittent freezes on my T41 where the screen basically freezes as it is, including the mouse cursor. It rarely seems to happen when I'm playing music, but on at least one occassion it has occured and the music stopped playing as well. However, I'm able to increase / decrease the LCD brightness using the fn + home / end keys, though the green bars that normally appear at the bottom of the screen to indicate brightness level do not show.

My thinkpad is currently out of warranty and I was hoping I could get some insight as how to isolate and fix the problem without having to send it in for repairs if possible. I used to have some other similar (but with different screen freezing effect) freeze problems that I seemed to have solved by completely disassembling my laptop and putting it back together.

On another note: I use my laptop very very often and frequently place it ontop of my bed / sheets, so the insides tend to collect dust (though I'm not sure which is the primary cause of the dust build-up). I try to open up the case and clean that out with compressed air when I can.