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...
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3. Click on the Options in the bottom-right of our On-Screen Keyboard, which brings up...
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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.
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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.
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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.