4. Replace the battery.
5.Turn the computer over so that the DVD slot faces you. Just below the center of the DVD slot, verify that the bottom case is flush with the front edge of the slot. If the case is slightly bowed and there is a gap, carefully pull the bottom edge of the DVD slot until it clicks into place and becomes flush with the bottom case.
DVD slot
Gap
6.Reconnect the power cord and any other cables. Restart your computer.
Warning: Never turn on your computer unless all of its internal, external, and case parts are securely installed. Operating the computer when its case is open or missing parts can damage your computer or cause injury.
10 - PowerBook G4 AirPort Card