hey i noticed yesterday that the fan & heatsink on my athlon xp (2100+) processor is pretty full of dust. can anyone please tell me how to go about detatching that clip that holds them to the mobo socket so i can clean them out? i built the pc, but have kinda forgotten exactly how the clip latches down & i don't want to exert too much force on anything in that area. is it correct that i'll also need to regrease the bottom of the sink with thermal grease? is this grease available at places like best buy or circ. city? thank you!