Ok,Put it face down on the screen,on something soft. Remove the screws out of the plastic bottom. The whole bottom snaps off. Then theres a slide in drawer with two cables connected to it,undo them and push aside. Undo the screws that hold in the drawer and pull it out.The CD and all comes with it.
There on the board is a black cover over the battery,snap it off and replace ,put the new one back the same way + and - . The battery is a one half lithium 3.6 volts. Slide the drawer back in and reconnect every thing. Be carefull around the board ...no static ..ground your self first.