Be sure to hold the display and upper case together with your left hand. Failure to do so may cause the freed display/upper case to fall, potentially damaging each component.
Remove the last remaining 6 mm Torx screw securing the display to the upper case.
Grab the upper case with your right hand and rotate it slightly toward the top of the display so the upper display bracket clears the edge of the upper case.
Rotate the display slightly away from the upper case.
Lift the display away from the upper case, minding any brackets or cables that may get caught.
Some 2.0 GHz A1278 MacBook Unibody logic boards do not have the necessary socket installed to accept the keyboard backlight ribbon cable attached to the upper case. The first and second pictures show logic boards with and without the socket installed, respectively. If your logic board does not have the backlight ribbon cable socket installed, the keyboard will work but the keys will not light up.
If your logic board does not have the socket installed to accept the keyboard backlight ribbon cable and you are installing a backlit upper case, simply tuck the keyboard backlight ribbon cable out of the way when you reinstall the logic board into the upper case.
Use a spudger to pry the fan connector straight up and out of its socket on the logic board.
It is useful to twist the spudger axially from beneath the fan cable wires to release the connector.
The fan socket and the fan connector can be seen in the second and third pictures. Be careful not to break the plastic fan socket off the logic board as you use your spudger to lift the fan connector straight up and out of its socket. The layout of the logic board shown in the second picture may look slightly different than your machine but the fan socket is the same.