I have a shuttle pc and an x800xt with stock cooling cuz thats all that will fit and keeping everything cool is starting to become a chore especially cuz temps outside are going up. So I want to make sure I get even a few degrees lower by replacing the thermal grease on my x800xt with artic silver 5. I really can't afford to screw anything up so I'm basically just wondering if there is anything I should look out for when taking off the stock heatsink because I have to put it back on. Has anyone done this before that can give me a few hints?