I just got to a point where I could re-install Avast but, as expected, it didn’t fix the problem. Besides the sound from Aimp, I only get sound in the device manager when I click the test button. No other program will cause a sound to be heard. Aimp does have a setting for choosing the playback device and it is set to the default device. All of the other programs don’t have such a setting that I can see so I assume they are using the default device too.
I realize this is off-topic for this forum so I won’t clog it up any further. I do appreciate the help in finding out Avast is not the issue.