It was time to contact Comcast. This was an exercise in futility. The chat bot wanted to reboot the set top box, so I let it do that. I got to see the welcome screen again, which wasn't what I had in mind.
So I finally found the phone number and called in. The useless phone robot insisted on resetting the set top box a second time (because the incompetents who programmed it didn't put in a hook to let it see that trick had already been tried). It then insisted that I had to wait until the already-determined-to-fail process completed before it would let me speak to an agent.
Eventually, it determined that the reset had failed and that I could now hold to talk to an agent. Or I could sign up for a call back at some indeterminate time. I decided to hold. *Then* it told me it would be a 45 minute to hour-and-a-half wait. And because the phone system was programmed by incompetents, there was no opportunity to change my mind.
While I was on hold waiting, I got a call back from Comcast to ask how my call had gone. I explained that it hadn't and they immediately hung up.
I also spent some time playing chat robot roulette to see if I could get some response from it. It would volunteer to connect me to an agent, but that would just throw me to a screen that said "We're really sorry about the virus and all that and we are not going to connect you. Why don't you try our lovely on-line resources?"
But eventually, I got a chat window agent. I explained the problem and he started working on getting me a replacement set top box.
A few minutes later, I got an agent on the phone. To his credit, he stayed on the phone with me while we verified that the chat agent had actually placed the order correctly.
So in two to three business days, I should have a working set top box for the upstairs TV.