You may rely on the accuracy of your Dell Latitude's clock in your home, especially if your computer sits on your kitchen counter. Your computer's CMOS (complementary metal-oxide-semiconductor) powers the CMOS chip. The CMOS chip is a tiny chip built into the Dell motherboard. It stores basic data instrumental to your computer's operation. This includes your computer's date and time settings.
If the CMOS battery dies, your Dell Latitude computer's clock settings will reset each time you restart the computer. Fortunately, replacing your laptop's CMOS battery requires almost no disassembly.
Shut down your Dell laptop. Disconnect all cables and/or devices. Close the display panel and place the laptop face down on a flat surface. Put on your antistatic wrist strap.
Rotate the laptop so the front edge is facing forward. Slide the battery release lever to the left to unlock the battery from its compartment. Remove the battery from the lower left corner of the laptop.
Remove the plastic modem compartment cover and using the Phillips-head screwdriver, remove the screw from the laptop's upper left corner.
Locate the blue CMOS battery inside the modem compartment. Pull the CMOS battery out of its compartment. Then disconnect the battery's cable from the motherboard. Remove the battery from the laptop.
Connect the new battery's cable to the connector inside the modem compartment. Place the new CMOS batter inside its battery slot inside the modem compartment. Replace the modem cover and its retaining screw.
Replace the main laptop battery and then reconnect all cables and devices to the computer.
Always wear an antistatic wrist strap when performing computer repairs to avoid any electrical damage to your Dell laptop.