[Patchicat]

Well, just for fun and grins, I went back to the links and attempted to download the necessary files one more time. This time, I succeeded in downloading all three files, installed them, and was able to sign in. And all my Barnes & Noble books showed up. I've redownloaded them onto the new computer. Since I already had them in Calibre, I'm not particularly concerned with future proofing them again, although I just might to be on the safe side. I guess the version I previously had downloaded from a while ago was the wrong version. Doesn't mean I'm going to resume purchasing from Barnes & Noble, however. It just means my books are no longer held hostage for the moment. Turns out that I have to tell my browser to download the files anyway as they are "not" secure. And the way around that is to right click on each file and chose save link in the dialogue box which comes up. Then you have to tell your browser to download the file anyway because otherwise, it's blocked. Hope this helps someone else.