[scarecrow420]

So does everything else work properly in WMC, just not the HBO channel? What about other similar channels? If you make a recording of the channel and try and play that back later in WMC, do you get the same issue? What audio format does HBO use?

Have you updated all the Intel drivers including the Management Engine Interface and graphics card driver (including the HD audio driver in the graphics package)? Im not sure if the problem is audio related but you could also just try running HDMI directly to the TV (cut the AVR out of the equation) just as a troubleshooting step.