I am trying to open an ebook that I downloaded from barnes & noble to my pc. I get a screen that says: This computer is not allowed to open......(book Title)..., to open enter info below; there is one box that asks for user name and the one under that asks for unlock code. I have tried using my adobe user name and password but they do not work here. Where can I get the unlock code and do I still use my user name for adobe.?