Ok, here's a quick and dirty explaination of what I posted earlier:
First of all hsf = heatsink and fan, the actual piece of hardware that cools your processor.
Second of all, thermal compound is a material that mates your processor to the actual heatsink. This material allows for a greater heat transfer from your processor to your heatsink.
On the matter of removing the old thermal pad or coating, you need something like aceton, rubbing alcohol, or wd-40. What you do here is look at the botton of the new heatsink and make sure that it has a thermal pad or some type of material in the center. This is easily distinguished by anything that is not copper (FYI, Cooper coolers are the best). Use the cleaning solution to remove all traces of the thermal pad or material.
After removing the stock heatsink, you need to carefully clean off all the old material from the processor. Take your time and make sure that the top of the processor is devoid of all materials.
Once this is done, you can check out the instructions on
www.articsilver.com which explain how to apply thermal compounds to your new heatsink and processor.
I hope this has cleared up any questions you may have, if not, post again and i'll try to answer.