Things You'll Need
Instructions
Open the battery door on the back of your Game Boy Color.
Remove the old batteries from the Game Boy Color by pressing down on the positive end of the battery, and lifting the battery out of the device.
Insert the new batteries into the Game Boy Color by pressing the negative end of the battery into the battery slot's spring, then pressing down on the battery.
Reattach the battery door on the Game Boy Color. Test the batteries by turning the device on. The "Power" light on the device will glow bright green.