Remove the following 6 screws and 3 nuts from the heat sink:

One 2 mm Phillips extending from a finger on the left edge of the heatsink and adjacent the firewire port (not present on some models)

Three 3 mm Phillips from around the fan (some models may only have 2 screws).

One 3.5 mm Phillips on the left side of the heat sink (not present on some models).

One 4.5 mm Phillips at the top right corner of the heat sink.

One 6 mm Phillips at the lower left corner of the heat sink.

One 4 mm nut from the right side of the heat sink.

Two 4 mm screw nuts with attached springs from either side of the heat sink.