One of the signs of a faulty Dell Dimension system battery is an incorrect date and time on your computer's clock. The clock may maintain its time as long as the computer is powered on. Once you turn off the system, the clock defaults back to "12:00." System batteries, like other batteries, eventually die and needs to be replaced. The battery is located on the motherboard of your Dell Dimension desktop computer.
Preparing to Replace the System Battery
Restart your computer. Press the "F2" function key on your Dell Dimension keyboard to enter the computer's set-up. Write down the settings and values on your computer's set-up screens. You will need to enter these values after you replace the computer's battery. Select "Exit" to close the set-up program. Do not save any changes when prompted to save. Turn off the computer and disconnect the power cord and any hardware cables attached to the system. Place your computer's new battery and a small flat-blade plastic screwdriver next to your computer so you don't have to hunt for them.
Opening Dell Dimension Computer
Lay the computer on its side. You will see an arrow on the bottom of the system's case. Arrange the computer so the arrow is pointing up and the back of the computer is facing you. Press the release buttons on the right and left sides of the case. Hold the bottom portion of the computer and raise the cover up.
Replacing System Battery
Locate the system battery next to the PCI card connectors on the right side of the computer's motherboard. Use a small flat-blade plastic screwdriver to gently and slowly pry the battery from its socket. Do not touch the motherboard or any wires around the battery. Once the battery is upright, use your fingers to remove the battery. Insert the new battery into the socket with the "+" symbol facing up. Snap the battery in place with your finger.
Closing Dell Dimension Case And Starting System
Arrange any loose cables within the computer's case so the cables are not in the way of the case's door. Push the case down on both sides until you hear the case click and lock. Reconnect any hardware cables to the back of the Dell Dimension. Make sure the network cable, if used, is attached to the router or modem first then connect it to the computer so the system will recognise the network connection.
Turn on your computer. Press "F2" when the Dell logo appears to enter the computer's set-up. Enter the information you recorded in Section 1. Save the changes when prompted to save. Your computer will then restart and boot into the Windows operating system.