Intel GA-8I915P - Manual (Page 27)

Hardware Installation - 27 -
English
19) BAT(Battery)
Danger of explosion if battery is incorrectly replaced.
Replace only with the same or equivalent type
recommended by the manufacturer.
Dispose of used batteries according to the manufacturer's
instructions.
If you want to erase CM OS...
1.Turn OFF the computer and unplug the power cord.
2.Remove the battery, wait for 30 second.
3.Re-install the battery.
4.Plug the power cord and turn ON the computer.