Q: Deauthorizing all 5 iTunes accounts w/out having a authorized computer??

You can't deauthorise 'dead' installations or computers you no longer have access to individually. However once you reach the limit of 5 authorisations you have the option to deauthorise them all in one go from your iTunes account and start over. *Just note that you can only use this option once a year*: About iTunes Music Store Authorisation and Deauthorisation

To deauthorise all computers associated with your account:

1. Click iTunes Store in the Source pane.
2. If you're not signed in to the store, click the Account button, then enter your account name and password.
3. Click the Account button again (your ID appears on the button), enter your password, and then click View Account.
4. In the Account Information window, click Deauthorize All.

Go here http://www.apple.com/support/itunes/store/browser/ and fill out the form. You should get help from the Store within 24 hours.

Hi,
I have a similar problem, where I only remember authorizing 2 accounts, yet my iTunes tells me that I authorized my limit of 5 accounts. I followed your instructions on how to reset these accounts, but once on my Account Information page, I could not see the Deauthorize All button... Could this be because i have an iTunes Canada account?
If I can not reset it this way, how can I do it?

Thank you,

Mathieu