DSJ,
Under the "Options" menu, there is an option called "Return to factory settings". This is a good starting place. Choose the option for 'MOST' settings as this will keep your audio and midi driver setup in place.
Also, have you tried writing a melody on the Soloist track to see if it plays?
Lastly, I notice that you have "LoopScn" active (it's above the staff on the right of the note name option). I wonder if this might be looping the leading section and not the notation section. Try deactivating this and see what happens.
Regards,
Noel