[Darryl Ramm]

And for after when you get audio input working.

Common problems with MIDI inputs:

MIDI Input "all" or correct input not selected
Midi Through not checked
Track not record armed
Using a MIDI or audio track when an Instrument track was needed
Not having a VI plugin inserted on the track

Enable the virtual instrument view in the mix or edit window and confirm you have the correct input selected, and that the track is seeing midi events (the small meter moves).

Still stuck:

Test with a different VI, like Mini Grand.

Check you can drive the VI using Windows>MIDI Keyboard

Things not working then go to more serious troubleshooting (vs check for user mistakes) with stuff like: trash prefs, test from a newly created admin account etc.

There have been occasional VI bugs where VIs do not produce output.