You might try changing your DNS Servers. The instructions are available elsewhere in this thread. Several people have suggested using the free Google servers at: 8.8.8.8 or 8.8.4.4
YMMV,
Good Luck.
Thanks, but I had already tried that. I also just now tried pointing at the Cloudflare servers, 1.1.1.1, and 1.0.0.1, and no joy.
In all the jumping through hoops I've done the last 24 hours, I have noticed what may be a clue.
I built this PC myself a couple years ago. It has a Gigabyte Z97X motherboard, i5-4690, 16Gb RAM, etc. etc.
There is a "Gigabyte App Center" running that monitors the MB, updates the BIOS, etc. A few minutes ago I clicked its, "Live Update" button, and it gave me a "no internet connection" error, which is the same error I get from Microsoft Store, and Windows
Update. I clearly have an internet connection, so why do these apps claim I don't?
The MB has a built-in Ethernet port, which I have disabled, but I'm wondering if somewhere deep in the bowels of Windows it's trying to get to the internet using that disabled ethernet port?