So I added the heatsink/fan assembly to the Z77 mPower motherboard without ever adding the i7 CPU. *facepalm*
How can I remove this assembly to insert the CPU? It has some plastic snap pieces that I can't seem to open:
On the top of the board, there should be a number of black buttons you pushed down when placing the heat sink. They should have some sort of markings on how to unlock them to pull them back up. (Usually by turning them 90 degrees) When they pull back up, the black pins you see in your picture automatically retract, enabling you to remove the heat sink.
Make sure you re-apply the thermal paste if it has spread out too far.