Before you can jerk the upper case off with joy, you must disconnect both the blue and white power cable and red and black speaker cable as described in the next steps.

Lift the upper case from the left side and use your other hand to pull out the right side in order to clear the power receptacle.

There may be a thin metal bar fastened to the upper case by the two screws on either side of the optical drive. This bar provides rigidity around the optical drive; don't forget it when reassembling.