Error trying to authorize new computer to transfer books to e-reader

[MWatson1219]

I had previously had my adobe digital editions on a computer that I recently got rid of. I am trying to transfer books from my library onto my nook using my new computer. I downloaded digital editions and downloaded the ePub books, but I cannot copy them to my nook in digital editions unless it is authorized. When I try to sign in with my adobe ID it says that I can't authorize with an ID that's been previously used on another computer or mobile device. How can this be? It says you can transfer items in up to 6 devices. Help please!

[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.