The Complementary Metal Oxide Semiconductor (CMOS) battery is used to store basic information about your Dell Latitude D600 laptop. The CMOS chip stores data regarding your system BIOS configuration, including the time, date, boot sequence and password. When the computer shuts down, the CMOS battery stores all the nonvolatile memory that would otherwise be "forgotten" when the power shuts off the computer. The CMOS battery is required to operate your computer and should be changed every five years for optimal performance.
Close all running applications and shut down your Dell Latitude D600 laptop. Unplug the power cord from the computer and transfer it to a dust-free work environment.
Remove the battery from the laptop by pressing the Battery Release Latch on the back of the computer.
Press and hold the reserve battery latch within the main battery compartment and rotate it outwards, exposing the CMOS battery.
Pull the battery straight out of the computer, being careful not to damage the wires connecting the battery to the computer.
Disconnect the CMOS battery connection from the wire that is connected to the speaker. Set the old CMOS battery aside and connect the new CMOS battery to the wires.
Insert the new CMOS battery back into the base of the computer and close the latch by rotating it towards the base.
Insert the main battery into the laptop and turn on the computer. You may need to set the time and date, in addition to other custom BIOS settings.
You will lose any customisations made to your BIOS when unplugging the CMOS battery from the system.