I may be off base here, but Truman, in your second post you wrote: "I was surprised to find that I couldn't hear any sound on the
piano keys (left of screen) and when I entered some notes and tried to play it back, no sound again."
Is this (in bold above) the keyboard that is on the left side of the Piano Roll View? If this is the case, I don't think clicking on those keys produce any sound. But if you click on an entered note in the PRV, yes you should get sound.
So if the above suggestions from the forum helped you get sound out of your system great!. Just don't expect the PRV 'keys' to make any sound.