What a day I've had! Gad, what a day!
Well, let's see. When I went downstairs, the DVR/cable box was finished setting itself up. I turned it on, and a momentary picture with sound and then the picture flashed off. I kept the sound but no picture. It kept doing this over and over. Each time I'd turn it off and cut it on, I'd get a momentary picture then it would go to black but with sound. I checked all of my connections. I swapped out the HDMI cables in case there was a handshake issue with them. Same problem.
Naturally, I called customer service again. They sent out a rep. We finally figured out that my HDMI switcher was interferring with the picture. If I took the HDMI straight into the TV, everything was fine. So now I know I can't use the switcher with the cable box. I'll have to go directly into the receiver with it. Irritating but at least it's functional now and I'll swap things around better tonight after I get my work project finished.