SRS is correct. I have opened machines which have never been cleaned and found them to be almost solid dust kitten. It is possible that once you remove the dust, the machine will be fine. You may also have fried your hard drive from too much heat. BACK UP YOUR DATA REGULARLY. If you are not fried, make sure the fan is running silently and at full power. If not, replace the fan and, as Dick O'Kane said, "Motor on."