Although the PN driver IS signed, I have found people are having issues with drivers from multiple sources sometimes, in some machines.
MS Dev does not seem to know the rhyme or reason.
Alternatively, people are simply turning off the 64bit signature test and things seem to be working fine then. Here’s the procedure, in case you have not heard of this solution
Press the Win + C keyboard combination to bring up the Charms Bar, then click on the Settings Charm.
We need to head into the Modern Control Panel, so go ahead and click on the Change PC settings link.
Once selected, you will see an advanced startup section appear on the right hand side. You will need to click on the “Restart now” button.
Since we are modifying boot time configuration settings, you will need to restart your Computer one last time.
Finally, you will be given a list of startup settings that you can change. The one we are looking for is “Disable driver signature enforcement”. To choose the setting, you will need to press the F7 key.
That’s all there is to it. 🙂 Your PC will then reboot and you will be able to install unsigned drivers without any error messages.