First you have to make a copy of itunes folder, then reinstall and you ensure that all options have them as in the previous installation.
Remember to go to Edit ==> Settings ==> Advanced
And change the location of the iTunes folder where shalt observe, Important do this before uninstalling and reinstalling!
Then you have to authorize the team == Store> Authorize to this team.
A failed me because I had no contact synchronization parameters as in the previous installation.
This also serves you if you're going to do is change the team and start sync with another PC, copy the iTunes folder and you take her to another PC, then install itunes follow the above steps.
I hope I have told you solved, greetings.