Bug - No display on screen

We used Proclaim Sunday morning without incident. Howeve, Sunday night, we could not get Proclaim to display on the screen through the video projector. Everything in the program seems to work fine. I had a video file I wanted to show, and when I played it, I could get the sound to play through our sound system, but nothing on the overhead screen.
To make sure there was no problem with our computer or video projector, I ran our Mediashout program and it worked fine. Retried Proclaim, but still nothing on the screen. All I see is the graphic we use for our PC desktop background. It's as if Proclaim is not sending anything to the video projector.
We have been using the program for a couple of months now, and we've never had this problem. The only thing we've done is that I paid for the yearly subscription this past week. But I even re-entered the license key, thinking it had somhow been deleted. No help.
Came back in this morning to see if I could get it to work, but still have no display on screen through the projector.