My DVR runs on an ATI Radeon 4550 adapter from MSI and SageTV. The video card works fine, supports HD Video and HDMI output and is completely fanless allowing my DVR to be super-quiet. Last time I rebooted my machine (I reboot about once every 6 months or so) the system asked me if I wanted to update my ATI Catalyst to the latest version available from my current version 11.12. I selected Yes and subsequently could not play a single video within SageTV. It appears that any Catalyst version higher than 11.12 on my system causes SageTV video to simply show the spinning loading logo forever.
To fix this issue, I had to completely uninstall the ATI drivers (via device manager – and check the box to delete the drivers off the system) and then uninstall the Catalyst software. Luckily I still had the installation files for Catalyst v11.12 in my downloads folder and was able to get back up and running by installing this version.
Working version of ATI Catalyst & Driver for Radeon 4550 on Windows 7 x64 and SageTV 7.1.9
Hope this helps someone else.