Numlock key wont activate

Hi all,
I just installed a new hard drive in the wifes computer, and installed Windows XP. The problem is, her numlock key won't work. When the computer turns on the numlock light is on, but once windows loads up it turns off and pressing the key does nothing. I thought maybe by having automatically it may solve the problem, but I have had no luck getting it to stay on.

I have tried changing the registry from 0 to 2, but when the computer restarts the light is on until windows loads up then the light goes off again still. When I go back into registry it has reset to 0 again.

I cannot work out why numlock will not activate when pressing it. There are no drivers for the keyboard as it is simply a wired keyboard with nothing fancy.

Some posts mention there being an option in bios, but I could not see anything for in hers (Gigabyte GA P35 DS3R).

Any help you can give is greatly appreciated