A lot of people are suffering after the Vista upgrade. I share your pain!
My iTunes music was de-authorized after upgrading. Too many MS fanatics are
blaming Apple. BS!
It worked in XP and MS broke it. Anyway, get the fix at
http://www.apple.com/support/downloa...orvista10.html. It
works. Run the tool while iTunes running otherwise some music files remain
de-authorized.