I have just installed a new Audio Interface on my PC running Windows 7. It works fine as an input device.. (and appears as a sound input device in Windows as one would expect).
However.. this device does not appear as an output device in Windows (it has both input & output capability).
[This means I can not select this playback recordings from my SonarLE programme for example].
Confession : I may have accidentally switched something off first time early after install when I first ran SonarLE which was related to this.