ok my fan makes a terrible noise so i thought maybe it's full of dust and needs cleaning so i open my laptop and on my attempt to remove the heatsink there are 4 heat sink screws one of them is impossible to unscrew it keeps going around and around and around without coming out and i use a magnetized tip screwdriver so even if it's loose in there it should come out and i tried to remove it with my nails and i poured a droplet of oil on it to loosen it but nothing..i don't know what to do.
here's a picture of it (circled in black and red): http://i.imgur.com/0t6Ev7C.jpg
here's a picture of it (circled in black and red): http://i.imgur.com/0t6Ev7C.jpg