Thanks, but when I set one of the books to 'open with' ADE2, I received "unable to download" "Error getting license. License Server Communication Problem: E_ADEPT_REQUEST_EXPIRED".
However, I just downloaded the book from my library 2 days ago, and the loan period is 2 or 3 weeks - although I don't know if that is the "request expired" that is being referred to - probably not. When I download the epub/ascm book from the public library, I am not prompted with any questions as to Adobe ID info or such, it just downloads the file directly to my downloads folder. I will delete them and try re-downloading the files while ADE2 is open.
Also, IF I sort this out, and in future want to drag & drop, exactly to where do I drag the file? Trying to drag to the Adobe Digital Editions folder or any of it's subfolders prompts an administrator permisssion ordeal from windows!
I am surprised to find that even the clunky process for borrowing library books for Kindle is much more straightforward than this; I had expected just the opposite. Thank you very much for trying to help. I just can't believe that I haven't been able to figure this out on my own and appreciate your help.