Trouble downloading eBook (authorize computer error)

[Guest]

I am trying to download a book from University Readers, and I accidentally clicked that I want to authorize without using an Adobe ID. Now it says it's unable to download because there is an 'error getting license'. I think I have an Adobe ID, so I need to be able to go back and input it instead of authorizing the computer to download without the ID. But now every time I restart and try to pull it up, it automatically comes up with that error and won't even let me choose to sign in.

[Nanaky]

Windows:

    Close all applications.

    Choose Start > Run.

    In the Open text box, type regedit and then press Enter. The Registry Editor opens.

    In the left pane of the Registry Editor, locate the following registry key: HKEY_CURRENT_USER\Software\Adobe\Adept

    Select the Adept key.

    Choose File > Export.

    In the Export Registry File dialog box, select Selected Branch under Export Range. Enter a name and location for the backup registry key, and then click Save.

    Right-click the Adept key and choose Delete.

    In the Confirm Key Delete dialog, click OK.

    Close the Registry Editor.

    Open Adobe Digital Editions and reauthorize.

Macintosh:

    quit Adobe Digital Editions.

    Navigate to /Users//Library/Application Support/Adobe/Digital Editions and drag the activation.dat file to the trash.

    If you are using 10.7, see https://helpx.adobe.com/x-productkb/global/access-hidden-user-library-files.html

    Open Adobe Digital Editions and reauthorize.