The battery in your Acer desktop computer is the CMOS battery. Your CMOS battery is what allows your computer to keep track of your BIOS settings when your computer is not connected to a power supply. Your CMOS battery will look like a large watch battery and is located on your motherboard. Removing your CMOS battery will require a screwdriver and will take about 10 minutes to complete.
Turn off your Acer computer and remove the power cord.
Remove the side of your computer case by removing the two screws that secure it.
Look at your motherboard. The CMOS battery will look like a large watch battery and will be located on the right side.
Gently pry out the battery with your fingers by lifting the edge of the battery.