I'm not sure you guys understood my concerns. My bad! As I said, I have a Sony PRS-600 reader and have been using it with Calibre with no problems. What I really like about using Calibre is that, when the Sony is plugged into my notebook PC, I can see all the books that I own in the Calibre library. There is also a list of the books that are on the Sony. There are check marks beside the library books that are also on the Sony and there are check marks beside the books on the Sony that are also in the library. I find that very useful. So far, I haven't figured out how to do that with the Nook. I'd rather not get into stripping the DRM in order to do that. I didn't do that with the Sony.
Since the Sony doesn't have wi-fi, I bought my books from the Sony book store, books on board, or borrowed them from the public library. I then transferred them to the Sony using Calibre. If I choose to operate that same way with B&N, will it operate the same as i'm accustomed to? If so, problem is solved and B&N support should have explained that? I am just frustrated that I can't even tell which books I already own without looking for them on the Nook. Remember that my books come from different sources. So looking in the B&N library doesn't show all my books in one place. I'm not interested in using the "Cloud" or the Nook "archive." I want all my files totally within my control.
Does the above explanation help to clear up my questions?