It never ceases to amaze me that people don't seem to apply their own basic intelligence to computers. The only advice I can give you is to use thermal compound in future.

If you motherboard has had it, this might be one of lifes learning experiences for you. It will hurt you in the pocket or your parents...

Yep, Arctos is 100% right, I've seen people ripping out half their motherboards trying to seperate their heatsink. I've managed to sucessfully seperate the ones I've come into contact so far, but this is probably more luck than judgment.