YAY! I've been trying to figure out WHY my Toshiba laptop was spontaneously shutting down. It is relatively new and I do all the maintenance things I'm supposed to (NAV, defrag, doctor, cleaning internet cache, etc.). I would get no warning, blue screen, etc. Just boom - complete shutdown. I followed your article and it was like a mirror! I pulled the heatsink out and there was 1/4 inch thick mat of dust, dirt, hair, etc. I did just as you instructed. My fan now runs intermittently on low, not on high. My computer is definitely running cooler. THANK YOU, THANK YOU, THANK YOU, THANK YOU. Diane M. Hess.