[Quixote]

For those who predicted that there is not an issue with the modem, you're exactly right....

I finally reached a CenturyLink service person on a chat line—the first one I'd ever come across who seemed to know what he or she was talking about. Asked me questions in a step-by-step manner—and I suddenly realized what the problem was.

Yes, only one DSL light was on; the other was dark. I looked more closely and noticed a crack in the insulation at the point where the jack connects to the modem. That was enough for the 'Aha!' light to go on.

Thinking that one of the wires might also have broken, I replaced the cable with a different one. A 'WOW!" moment: It works perfectly! Streaming using the Roku stick works perfectly! And this with the miserably low speed of 40 mbps—or close to it. Spouse is not ready to give up a conventional 'phone company land line,' and we just don't do anything elaborate that would require significant speed.

It serves our needs. Will that change in the future? Perhaps. Meantime it's working, and once again I thank my fellow ToTVers for your support, for the information and suggestions, and perhaps most of all, for your patience!