I too am having difficulty playing DRM protected content. I use Windows Media Center on Windows 8.1 with a HDHOMERUN Prime device and cable card. When I tune to any standard definition HBO channels (301-310) on WMC the audio is ok but the screen is black. Occasionally the HBO HD channel (300) will not even provide audio. Oddly, if I first tune to my local NBC station (810) and then tune to the standard definition HBO channels the screen displays correctly but this doesn't work for the HD channel. This is always a problem when using the DVR function with these channels as it will only record audio with a black screen.
I have reinstalled WMC as well as reinstalled PlayReady, but, have been unable to resolve the issue. Any suggestions or assistance is appreciated.
Most likely the computers you are using, have Intel Graphics Display Adapters. It's an issue with these on board devices that won't be resolved.
The only workaround for this is to add/replace a video card with one from a different manufacturer.