Once I syn new videos to my iphone. After the note of syn on iphone was shut-off (means completed), I disconnected the cable (but maybe too fast). After that, I can't use ipod any more. ipod display "no content". And itunes can't recognise my iphone. I can't syn my iphone with my PC now. But all others apps are operated in normal. Only can't use ipod and can't recogise by itunes.