This is because of an external keyboard or screenkeyboard was used,
on that, numlock was changed, and still in the system.
When you unplug it, with the numlock off on the laptop, but on on the keyboard,
you will have a difference and its activated in the system, what only can be helped with an external keyboard possibly.
Sounds difficult, most because of my explaination, but here is to do it:
1: Turn off numlock on your laptop.
2: Plug in an external keyboard.
3: Probarely numlock is on, turn it off on the External,
but leave the laptop allone.
4: Now its both off,
5: unplug the Keyboard
6: Now it will be fine!