Thank you for taking the time to provide some suggestions.
Unfortunately, the keyboard<-->computer connection is fine, and all software other than Unavowed has no difficulty with it.
Only Unavowed is failing, and it's not just the using-computer-ingame-scene, either. Unavowed won't recognize typing in its "Save Game" feature, where you're supposed to be able to type in a name for your save.
So something's wrong with Unavowed or related software (drivers, etc).