I have tried everything mentioned, and so far, no change. Even called my ISP Tech Dept, and had them do a reset from their end. Rebooted and steam still doesn't recognize my pc. So, now I will find a VPN w/ a free trial and try signing in from a different location. 4 hours and 10 new steam sign-in codes later I am still lost, lol. What I don't understand is that I played one day and all was fine. Next day, all was not fine. And I didn't do anything differently than I have been doing for a few months. Hopefully, the VPN will work (not sure how, but I gotta hope). I appreciate all the offers of help and attempts to fix my (and some other's) problem.
I don't know what making a VPN connection would do. So, you used someone else's internet connection and it still does it there?