I'm at a bit if a loss to understand why you needed a dedicated audio interface for "communication".....
Having said that, lots of people have a PC set up that can do all the usual PC things including gaming and also run a DAW like Sonar using ASIO drivers without any of the issues you appear to be finding. Certainly not to the point they can't get Sonar to even detect the interface drivers. What usually happens is that once ghe driver is installed Sonar sees it, you pick it in preferences and apart from adjusting things like latency that's it. And so long as the interface is switched on before Sonar loads Sonar will then always default to that driver.
In Sonar's preferences is a setting for allowing other applications to share the driver. Try ticking it. What it does by default is prevent Sonar keeping a lock on the ASIO driver and preventing anything else from using the interface, acting it means that if somethong else wants to access the audio system Sonar will allow it to. Though I doubt you'll get Sonar and something else operating in any kind of sync even if they happen to both play at the same time.
If you don't intend to use software synths or monitor what you record by getting Sonar to echo its input back to the audio interface outputs you don't even need to use an ASIO driver. The ordinary Windows WDM or MEE one will work well enough. ASIO is basically intended to reduce how long it takes the system to generate or modify audio down to the order of a few milliseconds, because with other types of drivers except WASAPI the amount of time it takes a computer to do the sums is long enough to be distracting at best and impossible to play in time with at worst. The problems set on for most people around the 10 to 20 millisecond mark. A WDM driver might have 50 milliseconds "round trip latency" which even gamers obsessed by instant respenses from the PC won't even notice, but for many serious music recording and production purposes that's an unacceptable amount of time.
But if you aren't doing the things that ASIO is intended to make possible, or at least much easier, you dont need to use ASIO drivers.
Which doesn't solve the curious problem of what it is about your setup that means Sonar is having the problems you describe, but might help you get things working.