I don't have a permanent solution, but here is the explanation from Dummies.com to what is happening:
The first thing the laptop designers decided to sacrifice on their keyboards was the numeric keypad. Rather than just saw off that end of the keyboard, laptops since the Model 100 have used a combination of numeric keypad/alphabetic keyboard.
This combination can be seen on your laptop by examining the 7, 8, and 9 keys. Note that these are also the top three keys on the numeric keypad. Because of this, a shadow keypad is created using the right side of the alpha keyboard.
Ok, all fine and good, but what about laptops that still have the numeric keypad, there is no need to activate this shadow keyboard.
A temporary solution; If you open up your on-screen keyboard and toggle the num-lock, it works correctly. So, you can turn on num-lock with the on-screen keyboard and then close the on-screen keyboard and everything works fine on your physical keyboard, but if you toggle num-lock on your physical keyboard it goes back to using the shadow keyboard.