Had an issue today the PC would/would not recognise the iPad but i could hear the bing as it connected,was visible in Device Manager,also the iPad had the pop up Trust/Don't Trust this computer but when i tapped the trust nothing happened still not visible in My Computer, tried another cable same issue, tried the iPad on another machine all good and well hassle free, so i disconnected the iPad downloaded a fresh version of iTunes and reinstalled on the initial pc, restarted connected the iPad and all works as it should..teacher happy =i'm happy:D