Turn the G4 over.

Remove the eight Phillips screws from the lower case.

Using your thumbs, slide the lower case away from you.

The lower case may stick in the front on a tab just above the center of the DVD drive. Be careful as you work the case off, or you may break the thin strip of plastic just above the drive.

Lift the lower case off.

Your laptop should look approximately like this.

Disconnect the hard drive ribbon from the logic board using a spudger or the tip of your finger.

To free the hard drive, remove the two T8 Torx screws from the right wall of the battery housing.

Remove the hard drive by gently grasping the orange ribbon cable and lifting the left edge up and out of the computer.

There are four rubber bumpers that fit over the hard drive screws. Ensure that these bumpers come out when you remove the hard drive.