1) Turn off all peripheral devices connected to the computer. Disconnect the computer’s power cord from the AC power source (wall outlet or power adapter).
2) Remove the computer cover.
3) Locate the battery on the board.
4) With a medium flat-bladed screwdriver, gently pry the battery free from its connector. Note the orientation of the “+” and “-” on the battery.
5) Leave the battery out for 10 - 15 minutes, for the CMOS to lose the settings.
6) Replace the battery in the connector, orienting the “+” and “-” correctly.
7) Replace the computer cover.
8) Turn the system back on.