How can I deauthorize dead computers?
You need to use the Deauthorize All function.
If you "Deauthorize All" in order to deauthorize computers no longer in your possession and then you "authorize" the computers still in your possession-- do you lose everything in your itunes?
No. Back it up anyway.
Dumb question-- how do you backup itunes?
Click here and follow the instructions.
What if you deauthorized 4 months ago and now it won't let you deauthorize until 9-11-2014?
Bill in Las Vegas
Retrieving data ...