HT1206

Do you want to know how to deauthorise all your computer's iTunes or something else ?

If all, and you've reached the 5 computer limit then you can log into your account and 'deauthorise all' (which you can do once every 12 months) and you can then authorise/reauthorise the computers that you still have and need : authorising and deauthorising.

If you mean something else ... ?