With the Windows 10 upgrade, iTunes is treating my laptop like it's a new device. This means some of my older purchases - which I made using email addresses I no longer use - are no longer authorized. When I try to (re)authorize my laptop, it brings up on old address and asks for a password I no longer have.
If I ask to reset that password, the request will go to the old, dead email address. Meanwhile I can't update my iPod without losing the "unauthorized" songs.
How can I bring everything under my current account and make sure my laptop is authorized for all the purchases?