Quote David Bolstridge:
I've selected stereo tracks on cakewalk.
I'm not a Cakewalk user I'm afraid, but I suspect there will be a way of allocating the sound card's physical inputs to the DAWs virtual tracks, and that's the first thing to check.
The next thing would be the sound card's own configuration software and the operating system software relating to the sound card. Not sure if you're using PC or Mac, but you may well find there's a configuration mode in the OS that selects inputs, mono mode and various others things. Worth checking that. The sound card itself probably has some kind of input and output router/mixing application that also needs to be checked.
Technical Editor, Sound On Sound