Place five drops of thermal grease on the CPU in the pattern shown. Lower the assembly into position over the CPU. Tighten screw number 1 halfway, then tighten screw number 3 all the way. Finish tightening screw number 1. Tighten screw number 2 halfway, then tighten screw number 4 all the way. Finish tightening screw number 2. Reconnect the heat sink to the systemboard. Repeat for the other heat sink.
Lower the optical disk drive frame into the chassis and rotate it down. Press it down to secure it. Slide the optical disk drive into the slot until it clicks. Reconnect the signal and power cables.
Insert the three clips into the holes in the chassis and rotate the bezel until it snaps into position.
Lower the cover into position in the guides and close the cover.