Removing the retail SECC2 heatsink can easily be done without breaking anything. You can even reuse the stock HSFcartridge if needed. All that is required is a pair of curved needle nose pliers. Straight nose can be used but you will need to use something for a fulcrum to make them work properly. Just follow the steps below and you can pop that retail off as easy as 1-2-3!
The pictures are ordered in the clockwise direction.
Push tab on the end of the fan assembly and pop it loose from the heat sink. Then do the same for the tab on other end of the fan assembly. The fan assembly should now pop off the heat sink.
You can see the 4 pins, which hold the heat sink on to the back cover. Here's a close-up, you can see it's actually 2 plastic brackets with a pin on each end. You can see the "threads" on the end, which hold the bracket to the back plate.
Using a pair of curved needle nosed pliers, slip them under the ring on the pin post and push down on the handles of the pliers. Rock the tips of the pliers up and pull the pin out of the back plate. You will hear some popping sounds, don't freak out you aren't breaking anything. It's just the plastic "threads" on the pin pulling out of the back plate. Straight needle nose pliers will work also; you just need to put a piece of wood or the handle of another pair of pliers under them to act as a fulcrum. I used a paintbrush handle in this pic.
Pop the pin all the way out till it moves freely. Then do the same thing to the pin on the other end of the bracket. The bracket is now free and can be removed. Now you need to do the same thing for the bracket on the other side of the heat sink. The heat sink can now be removed from the CPU card.
Now depending on what fanfan or perhaps a water-cooling block you are going to apply, you may need to remove the back plate.
There are 2 small mushroom head pins holding the back plate on. It is the black pin you see in the center of the picture, the one on the right is just a support pin. You can see the actual pin in the pic; again it's the pin in the center. To remove the back plate all you need to do is squeeze the head of the pin using your trusty needle nosed pliers and pull up on the CPU card so it slides off the pin. Now do the same thing for the pin on the other end of the card and you should have a bare cpu!
Now having taken the retail heatsink and fan off, lets see if we can install a more powerful one.