I am not familiar with the issue myself, but if you believe the issue has something to with the state of the numlock key in Windows 8, you may want to consider activating it on boot. Looking online, there are some websites with tutorials on how to do this. For example,http://thetechjournal.com/how-to/tutorial-how-to-activate-numlock-upon-boot-in-windows-8.xhtml
Please be careful whenever editing the registry on your machine. I have not tried the tutorial here and cannot vouch for its safety or effectiveness.
If this does work for you, please come back and let us know.