1. In Ease of Access, turn on On Screen Keyboard. This is to show you what transpires next.
2. With On-Screen Keyboard on, like this...
3. Click on the Options in the bottom-right of our On-Screen Keyboard, which brings up...
4. ... and click on the Turn on numeric key pad check box and Click OK. You should now see the NumLock button at the bottom right corner.
5. Click on it to enable it. You should now be able to type numbers with the On-screen Keyboard and the Numeric Pad should work as expected.
6. If you do not want to use the On-screen keyboard, press the Clear key under F16, which toggles the NumLock without the On-Screen Keyboard. Please test and verify.