Nah, not overclocking until i get a new heatsink, anyway, whenever I seat the heatsink all the pins go in and are locked in to place, but one always stays a bit loose. If i get all 4 tight it kinda bends the motherboard :S
happens on my friends lga775 also, wierd :S
That one pin that is staying loose is enough to cause a thin gap between the heatsink and the surface of the CPU and that's the gap that can trap heat and not drain it away.
Look up youtube on techniques on how to get 4 pins down correctly (cross or star pattern).