Dell desktop computers use a battery in the motherboard to keep certain functions constantly running. Some of the functions are remembering the correct time and date on your computer. When your computer is not keeping the right time or is giving you a BIOS error, it's time to change the battery on the motherboard. Changing this battery is not hard and will not require a computer specialist. You can do it yourself with little hassle.
Unplug your Dell desktop computer's power cable.
Use a screwdriver to remove the screws holding the cabinet door onto the computer's casing.
Remove the cabinet door so you have access to all of the components inside the computer.
Turn the computer over on its side and locate the BIOS battery. This battery will look similar to a watch battery.
Push on the release lever to take the battery out of the computer. Replace the battery on the motherboard.
Put the computer casing back together and replace the screws holding the cabinet door onto the Dell's casing.
Plug the computer back into the power outlet and turn it on.
Replacing the battery will reset all of your BIOS settings.