How to Turn on or Enable NumLock (Numeric Lock Key) by default
For Windows XP

To turn on Numeric Lock for a user on your computer in Windows XP, do the following:

Click start, then click run.
Type regedit there and press enter.
On the left hand side, go to HKEY_CURRENT_USER\Control Panel\Keyboard\InitialKeyboardIndicators
(Go to the sub menus by double clicking the menu. For example double click control panel to open up the menu)
Change the value there from 0 to 2
Then turn on Numlock key manually using the keyboard button “NumLock”
Then log off your computer. To do so, click start, then click Log off. Then log on bank again.
If you have set up more than one user on your computer, then you can make the same changes for all users again by modifying value from 0 to 2 at HKEY_USERS\.DEFAULT\Control Panel\Keyboard\InitialKeyboardIndicators

So that is how you turn on the Numlock key by default when windows xp starts up .

See more advanced and general free Windows XP Tips and Tricks for various purposes here. Everything is totally free here.