Oh, and it is really important to clean all of the old thermal grease off of there. This stuff http://www.newegg.com/Product/Product.aspx?Item=N82E16835100010 is the best for it. You can use rubbing alcohol if you're on a budget though, it just takes longer.
Another thing, I have heard of people using a hair dryer to manually heat up the back of the board. I've never tried it myself, but it could work as a last resort..
Another thing, I have heard of people using a hair dryer to manually heat up the back of the board. I've never tried it myself, but it could work as a last resort..