Thank you, hazelnut, for taking the time to respond. That lifted my spirits because I am always heartened by the generosity of others to help complete strangers.
I wrote my initial post about 2 hours into my troubleshooting frustrations. When your response arrived I was still troubleshooting, removing drivers, updating drivers, etc. etc. The next step would have been implementing your suggestion to restore and roll back my system, but I got the camera working again without having to do that. I’m still not sure which ‘fix’ was the one that worked, but I know it wasn’t anything I found in a Windows or Dell help article. It only started working again after I went to Dell’s support website and pulled down a number of drivers and installed them manually.
I’m thankful to have ‘only’ lost 3 hours of my life to this misery, plus a couple of virtual calls where I had to explain why my camera was off. But, as you might guess, I’m not planning to pay for a CC subscription when my trial expires.
Thanks again for taking the time to assist.