Shut down the computer
Unplug the power cable
Remove the laptop battery if applicable
Press and hold the power button for 10 to 15 seconds
Open the case or access panel
Locate the CMOS battery on the motherboard
Gently release and remove the CMOS battery
Wait 5 to 10 minutes
Reinsert the CMOS battery
Reassemble the case or access panel
Reconnect power and battery
Turn on the computer