Q: itunes won't download because something about "mobile device not authorized?"

Hi buckirich,

Thanks for using Apple Support Communities.  It sounds like you may need to restart the Apple Mobile Device Service.  This article has instructions for doing this:

How to restart the Apple Mobile Device Service (AMDS) on Windows

http://support.apple.com/kb/ts1567

If that doesn't resolve the issue, I would recommend trying a thorough uninstall and reinstall of iTunes as described here:

Removing and reinstalling iTunes and other software components for Windows Vista, Windows 7, or Windows 8

http://support.apple.com/kb/HT1923

Cheers,

- Ari