i cannot synch anymore my ipod, why?

I was synchronizing without problems while I left my ipod connected and started to watch a movie on itunes. as mistake I closed itunes, opened again but trouble on trobles were coming. apparently I did not make anything so drammatic and if any problem was coming, I do not believe it could be related to any software. maybe the ipod disk is damaged but while i try to exames it, errors are coming. I made ipod reset several time and also upgrated the itune softwaere, no way, it starts to synch but, after a while, it stops because the program cannot write there anymore! :( Help!!!! Grazie Fabio