I bought a computer back in 2007 and just recently took off the heatsink fan to clean it, omg there was so much dust in the heatsink. Like clumps of it... the heatsink is attached to the motherboard by screws. anyways i noticed the thermal paste was dried up and i have no idea how long it has been like that. But my cpu never shut down from overheating or anything and it still works. the cpu is a q6600. Should I reapply thermal stuff or is it supposed to be dry?