Downloaded a book without ID, how can I authorize the computer and add the book after authorization?

Hello,

I have bought a book online, then downloaded it on my computer, but I chose to continue without an ID (I didn't know anything about the digital editions yet). After I downloaded the book I knew that it can't be downloaded on another computer. Originally the book is not for me. Is there any way I can add this book to an ID?

Thank you.