The CMOS battery, called a reserve battery by Dell, powers a computer's real-time clock and NVRAM (nonvolatile RAM). NVRAM contains certain user-specific system parameters that will all be lost when the CMOS battery is removed. This means all time and date settings and system parameters will be reset to defaults. Removing this battery in a Dell Inspiron laptop computer usually requires removing several components for access before reaching the battery.
Shut down the computer.
Remove the main battery.
Remove any device from the media bay by pushing the latch unlocked and sliding the device out of the bay.
Remove the keyboard assembly screws from the underside of the case. They should each be marked with a "K."
Turn the computer over and open the display.
Insert a small, flat-blade screwdriver under the edge of the blank key and gently pry up the right edge of the keyboard.
Lift the keyboard up and rotate it left, then disconnect the keyboard cable and track stick cable from the keyboard.
Remove the keyboard.
Close the display.
Remove the display screws from the back of the computer. They should be labelled "Circle D."
Open the display and disconnect the display flex cable from the main board.
Lift the display assembly from the bottom of the case and pry the hinge cover loose from the snap tab at the bottom of the display assembly.
Remove the palmrest screws from the bottom of the computer near the front. They should be labelled with a "P."
Turn the computer right-side-up.
Disconnect the palmrest cable from the touchpad connector on the main board and remove the palmrest assembly.
Disconnect the reserve battery connector from palmrest bracket.
Tear the battery away from the foam pad on the palmrest bracket.
Remove any remaining foam from the palmrest bracket.
Connect new battery cable to connector on the palmrest bracket, then insert the battery.
Reinstall all the components you removed in reverse order.
There may be slight variations in removal procedures for specific components on different Inspiron models.