for some reason my computer is authorized to an old email address, so my library books won't work because they are checked out to a newer email address. How do I change which email address my computer is authorized to so that I can read my library books on my nook?
Case1: If you like to remove the old authorized account and authorize with new account.
Case 2: If you like have Multiple Accounts.
In this case, the ADE is activated with Multiple Accounts and you can switch you default accounts.
Hope this helps you.