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.
If your G4 has a CD-RW or Combo drive, the pictures in the following steps will not exactly match your computer.
Before continuing, place a soft cloth on your work surface to rest the computer on. Turn the G4 over, making sure the DVD drive doesn't fall out. Place the computer on the cloth.
Performing the following steps incorrectly can easily damage the display and render it inoperable. The multicolored display data cable is especially fragile.
Remove the four black T8 Torx screws from the plastic framework.
Open the display to a 90 degree angle. Rest the trackpad face down on the work surface and allow the display to hang over the edge. If possible, adjust your chair or work surface height so the display will rest on your legs and the trackpad will lie flat on the work surface.
Remove the four T8 Torx screws that fasten the display to the trackpad. The screw closest to the display data cable has a tapered head.
Grasp the metal heat exchanger and pull up and away from you. You may need to move the inverter cable on the right side of the computer in order to rotate the heat exchanger.
Disconnect the inverter cable and carefully thread it through the slot in the upper case.
Carefully thread the display and backlight cables individually through the slot in the upper case. Be very careful with the display cable as it is easily damaged.