Lenovo ThinkPad T43p - Manual (Page 42)

If the keyboard problem is resolved, carefully reconnect the external
numeric keypad, external keyboard, or mouse, making sure that you have
seated the connectors properly.
If keys on the keyboard still do not work, have the computer serviced.
Problem:
A number appears when you type a letter.
Solution
The numeric lock function is on. To disable it, press and hold Shift; then
press NumLk.
Problem:
All or some of the keys on the external numeric keypad do not work.
Solution:
Make sure that the external numeric keypad is correctly connected to the
computer.
Problem
Some or all of the keys on the external PS/2 keyboard do not work.
Solution
If you are using the ThinkPad Dock II, the ThinkPad Mini Dock, or the
ThinkPad Port Replicator II, make sure that the keyboard cable is correctly
connected to the keyboard connector.
If the connection is correct, disconnect the cable and make sure that the
built-in keyboard operates properly. If the built-in keyboard works, there is
a problem with the external keyboard. Try using a different external
keyboard.
UltraNav problems
Problem:
The pointer drifts when the computer is turned on or after it resumes
normal operation.
Solution:
The pointer might drift when you are not using the TrackPoint during
normal operation. This is a normal characteristic of the TrackPoint and is
not a defect. Pointer drifting might occur for several seconds under the
following conditions:
v When the computer is turned on.
v When the computer resumes normal operation.
v When the TrackPoint is pressed for a long time.
v When the temperature changes.
Problem:
The mouse or the pointing device does not work.
Solving computer problems
20 ThinkPad ® T40 Series Service and Troubleshooting Guide