unable to authorize another computer

[karenp50899015]

I purchased a new computer, and downloaded ADE,   when I go to authorize ADE with my Adobe ID, so I can download books from my  local library, I get the message

./. you can only authorize this computer with and Adobe ID that hasn't been previously used to authorize any other computer or device /.....

I deactivated the old computer, but still get the above message.

thanks

[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.