Enabling NUM LOCK before the logon screen -
Check BIOS settings - For NUM LOCK to be on prior to the windows login screen, this would be controlled at a BIOS level. Most modern systems have a BIOS option to enable NUM LOCK during the system startup. (Note - This does not change the setting in windows for the Logon Screen)
Enabling NUM LOCK for the logon screen -
Change the System Setting key as indicated below. The Current User Setting is to change it for only the current person logged in. The System Setting is to change it for all users.
[HKEY_CURRENT_USER \ Control Panel \ Keyboard] {Current User Setting}
[HKEY_USERS \.Default \Control Panel \ Keyboard] {System Setting}
InitialKeyboardIndicators = "0"
"0" - All Keys off
"1" - Caps Lock on
"2" - Num Lock on
"4" - Scroll Lock on
For multiple keys, add their values:
"3" - Caps Lock and Num Lock on
"5" - Caps Lock and Scroll Lock on
"6" - Num Lock and Scroll Lock on
"7" - Caps Lock, Num Lock, and Scroll Lock on
"2147483648" - Honor the motherboard BIOS setting (Vista only)
More Info -
MS KB Q154529 (Merged with Q315468)