[header] How to deauthorize itunes [title] Open itunes on the computer that you want to deauthorize. [step] If the computer that you want to deauthorize is no longer available, see the following section. [title] Click the store menu. 
[step] From the drop-down menu that appears, select " deauthorize this computer..." [title] Enter your apple id and password. [step] Click the deauthorize button.