I recently replaced Holly's laptop with a Vista desktop at the house (I'm not being cruel, she never took the laptop off the dock) and have been working on getting it dialed in just how I want so that it can double as a Media Center, development box and media hub. The whole process has been both educational and frustrating and maybe sometime I'll reflect on the entire process, especially some of the nasty issues with the ATI Catalyst drivers. However, I've just gotten past the last big problem I was having and thought I would share. When I bought the box, it came with Vista Home Premium, but I needed some of the business grade tools that come with Vista Business and Vista Ultimate, so I did an "Anytime Upgrade" to put Ultimate in place. After upgrading, however, I had to re-install the Sigmatel driver for my sound subsystem since the upgrade screws that up. After doing so, however, I started having issues playing any of the tracks that I downloaded through my Zune Pass subscriptions when using that machine. The files played fine on the Zune itself or when streaming, but failed when downloaded to the PC with this error: "C00D7159: The policies that the Input Trust Authority requires to be enforced are unsupported by the outputs." After messing with this for way too long, I finally discovered that this is a driver signing problem. If Vista is set to bypass its check for signed audio drivers, the trust pipeline required for DRM is broken and therefore Zune (and WMP) won't play the protected content through that device. Vista can be forced back into checking for signed drivers by setting the DisableProtectedAudioDG registry key at HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Audio to a value of 0 instead of 1. Changing that and rebooting fixed the problem right up! NB: I have absolutely no idea what happens if you make this change and the driver for your audio system is NOT signed. My assumption would be that it would prevent the driver from loading, but it could be less than graceful and lead to system instability. Also, I'm fully aware that I'm supposed to launch into some screed on the evils of DRM at this point in order to keep my Geek card membership in good standing, but honestly, it's not worth the effort. (Plus my views on DRM aren't quite that simplistic . . .)