Enable the NUM LOCK key for the logon screen

To enable NUM LOCK before a user logs on, use the steps below.
1.
Run Registry Editor (Regedt32.exe).
2.
Navigate to HKEY_USERS\.Default\Control Panel\Keyboard.
3.
Change the value for InitialKeyboardIndicators from 0 to 2.


Support:
http://support.microsoft.com/kb/154529