Locate the battery release tab on the underside of the G4.

Slide the battery release tab to the left and lift the battery out of the computer.

Remove the seven T8 Torx 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 optical 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 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.

Your laptop should look approximately like this.

Disconnect and remove the indicated orange ribbon cable.

Disconnect the pink and white inverter cable from the inverter board.

The display inverter has orange plastic shielding around it that looks similar to the tape used elsewhere within the computer. Do not remove the shielding from the inverter.

Remove the two silver T8 Torx screws from the black plastic bar.

Lift the black plastic bar out.

Reassembly will be significantly easier if you reseat the hard drive before returning the black bar to its place.

Disconnect the two orange connectors from the logic board, removing tape as necessary.

Lift the drive up on the right side so that you can access and disconnect the modem cable and inverter cable.

Remove the drive by lifting the right edge up and out of the computer.

Remove the 4 T6 Torx screws securing the modem and inverter boards to the optical drive.

Lift the inverter board off of the optical drive.

Lift the modem off of the optical drive, carefully guiding the orange cable through the metal mounting bracket.

Disconnect the orange optical drive ribbon from the back of the drive.

If your new optical drive already has a bracket and bezel for your model, then you are done.

Remove the 2 Phillips screws from the side with the longer bumper.

Remove the bracket from the optical drive.

Remove the 2 Phillips screws from the other side of the optical drive.

Remove the bracket from the optical drive.

Depending on the new drive's model, the bezel on your old drive may not transfer to the new one. The bezel is not strictly necessary, and the drive will probably work fine without it, but you should transfer it if you can in order to ensure proper alignment with the case.

Remove the 4 Phillips #00 screws from the top of the optical drive.

Lift up on the thinner edge of the optical drive so that you can access and depress the recessed black tab using a spudger.

Use a spudger to depress and release the two black tabs on top of the optical drive directly over the bezel.

Use a spudger to depress and release the black tab on the left side of the optical drive.