Correct on the first one I am going to assume, correct me if I am wrong lol.
Like I said, the easy, cheap, and quick thing to try at this point is just get as much dust out as possible.
Dust --> Heat --> decreased performance -->(eventually) crashes
Noo, noo, it cant be Dust problem, I clean it every week. It collects alot of dust =D
Antec Nine Hundred tower.