If you have the Problem that iTunes ask on every sync to authorize (activate) your computer again here is an easy way to fix this.

I had this problem today once again, and now I decide to post this solution again.

- Make sure that in your explorer the option is active, that you see hidden files and directories - Navigate to the folder C:\ProgramData\Apple Computer\iTunes - Inside this folder you will find another folder with the name “SC Info” - Delete it! Yes simply delete it. - After you open iTunes once again, it will configure some things and ask once more (the last time!) for the activation/authorizing

And that was all. Till now it has always fixed my problem. Hopefully it will also work for you.