To use Tuner.exe with any sound device other than the built in soundcard you have to use the Windows Control panel to set up the aftermarket sound device as the default Windows System Sounds device. Be sure to have Tuner program shutdown completely before doing the switchover, then open the program.

Alternateively, you may be able to use the Tuner via the built in sound device if the computer has a built in mic but you would have to open the builtin sound applet by doubleclicking on the little speaker in the taskbar, then use the File Options to go to the Record Options and make the mic hot, also adjust the volume fader for that mic appropriately. Then anything heard "in the air" in your room should be picked up and sent to the Tuner program. Sounds like that is what is happening at your end already, but perhaps the mic fader for Record is turned down, or the Mute may activated. Important to make sure the Playback fader for that mic is Muted, or feedback can occur.

It is likely not responding for you at the moment because the Windows OS is still set to use the internal soundcard.

BTW Tuner.exe can run standalone if desired. It is located in the bb folder and a Copy can be made and placed on the Desktop or anywhere else and yield a handy Chromatic Tuner available nearly instantly. Nice.

--Mac