Removing the Battery on the original iMac G5
1.To access the battery the AirPort Extreme card may have to be removed. This procedure will show you how to remove and replace the card.
2.Important: Ground yourself. Touch the metal surface (as shown below) on the inside of the computer to discharge any static electricity.
Warning: Always discharge static electricity before you touch any parts or install any components inside the computer. To avoid generating static electricity, do not walk around the room until you have finished installing the part and closed the computer.