Hello, in this image; http://img713.imageshack.us/img713/8905/photobhv.jpg I have removed the clamps which hold the mini-heatsink in place, however, the heatsink itself will not budge. I have to apply new thermal paste so I need to get under the heatsink, what's the problem?
The heatsinks may have thermal epoxy on them and be unremovable without damaging the board or component? You can try warming the heatsinks or board but if they heatsinks don't move, I'd expect they are epoxied.
Get a hair dryer and blast the heatsink for a minute or so. Then try and remove the heatsink, and as has already been said, a twisting motion will help. Some TIM will set when cool, but it becomes pliable again when it is heated.