Why isn't the numeric keypad working in Windows XP?

[CRGreathouse]

I'm trying to fix a problem with a computer system and I'm not sure where to go next.

My office manager said that her numeric keypad wasn't working, though the keyboard was otherwise fine. I replaced her keyboard but to no effect: the new keyboard worked fine except for the numeric keypad.

On further investigation the keypad works normally when num lock is off, acting as arrow keys, but when num lock is on I don't get anything.

The computer is running Windows XP. Any ideas of what might be wrong?

 

[QuantumQuest]

As the keyboard has been replaced and the problem repeats itself, it is most likely the "Use Mousekeys" configuration that causes the problem. For Windows XP the steps to change this configuration are:

Start -> Control Panel -> Accessibility Options -> Mouse. Here, uncheck "Use MouseKeys". Then go to Settings
-> "Use MouseKeys When NumLock Is:". Here, you select "Off". Then push "Apply" and finally "OK".

We can come across this same problem in other versions of Windows as well, including recent versions.

A less common cause for this problem is keyboard drivers. If the above procedure does not solve the problem then the next step is to uninstall / reinstall keyboard drivers.