Things You'll Need
Instructions
Turn off the power to the Game Boy and remove any games, adapter cords or other paraphernalia from the device.
Flip the Game Boy over and locate the small screw in the center of the device.
Loosen and remove the screw with your screwdriver, then put the screw aside. Pop off the battery panel.
Remove the old battery from the battery compartment.
Place the new battery into the compartment in the same manner as the old one.
Replace the battery cover and secure it with the screw.