Adobe Digital Editions

Good Evening,

For a year or so I have been borrowing digital books from my public library with no problems.  On the weekend I changed computers and how digital editions won't let me copy the book to my KOBO and when I try and register I am told that my account is already registered on a different computer and I can't use the same email and log in.

I don't want to sit at my computer to read a book from the library, I want to be able to take my KOBO and read it that way.  What am I to do.  I feel so frustrated, its all too technical for me and very little connection to actual help.  Please help me.