CMOS Failure Symptoms:

Incorrect computer date and time settings. (This is the earliest sign that lets you know when the time is right to get a new CMOS battery.).
The computer occasionally turns off or refuses to start.
The laptop could not find a printer.
Malfunctioning of the mouse.
Problems launching a program.
Beeping sound from the computer.


Compatibility :

IBM Thinkpad 570 Series -- 570, 570E, 570X, 570Z 
IBM ThinkPad A Series -- A20, A20P, A20M, A21, A21E, A21M, A21P, A22, A22M, A22P, A23, A30, A30P, A31P 
IBM ThinkPad T Series -- T20, T21, T22, T23, T30 
IBM ThinkPad R Series -- R40, R40e, R50, R50e, R50p, R51, R52 
IBM ThinkPad X Series -- X30, X31, X32 
IBM xSeries -- 300, 400

IBM P/N: 02K6541, 02K7087, 02K7075, 08K8050, 08K8216,FRU-02K6572, 92P0991, 92P0986 

Package : 1 piece of CMOS battery