I just read ebooks on my PC with adobe digital reader 3.0 before I had an Adobe ID. Now I would had like to read my ebooks on a tablet. So I copy an ebook on my tablet to read it. There was the message that I have to establish an adobe ID. I did and I authorised my tablet. After it I would authorise my Pc too, but there was the message that I can't authorise this PC when I have already used it for other apparatus for authorising. Now i dont know, what to do.