I am upset that the HPS50 will not work with Windows 8.1. If I would have known that I would have purchased a different scope.
The Error on driver installation is…
A problem was encountered whill attempting to add the driver to the store
Please fix it!!!
OK I figured it out. I was using the updated driver inf file for windows 8 that I found in the forums here,
http://www.velleman.eu/downloads/files/downloads/hps50-win8.zip
The problem was with Windows device driver signing. You need to disable Driver Signature Verification on 64-Bit Windows 8.1 (So That You Can Install Unsigned Drivers). If you do not know how to do the here is a link to a tutorial.
http://www.howtogeek.com/167723/how-to-disable-driver-signature-verification-on-64-bit-windows-8.1-so-that-you-can-install-unsigned-drivers/
Do that and you can install the drive and it works fine.