Suddenly my nano (6th Gen.) i pod has been detected but not properly identified in iTunes. I disconnected and reconnected. Nothing. I uninstalled i Tunes and re-installed it but still wont work.

I have been able to transfer music from i Tunes without any problem until today, when I connected the nano to the computer a messages appeared on the screen syaing the i pod had been detected but not identified. I followed their instructions to disconnect and reconnect the i pod., that didnt work so I unintalled i Tunes and reinstalled it. But that has done nothing. I am running windows 8.1.Has anyone else had this problem?