CAUTION: Even though the heat-sink assembly has a protective plastic covering, be careful when touching it -- the assembly may still be hot if your PC was just on.

Release the blue plastic secure lever under the heat-sink assembly by pushing the tab and pivoting the lever down and away from the assembly.

Remove the two screws located at the top and bottom of the heat-sink assembly using a standard Phillips-head screwdriver.

Pull the heat-sink assembly off the board as if it were a door with its hinges on the right.

Clean the old thermal paste from the contact points on the heat sink