1.Open Adobe Digital Editions
2. Press CTRL+SHIFT+D after selecting the ebook you need to remove.
3. Deauthorize Computer screen will appear explaining – "Are you sure you want to deauthorize this computer? If you have protected items in your Digital Editions library, they may no longer be readable."
4. Select "Deauthorize"
5. After selecting "Deauthorize" – a message will appear stating
"Your computer was successfully de-authorized. Restarting Adobe Editions will require you to reactivate your computer."
6.Click on "Quit"
7. Adobe Digital Editions will close