My iPod Touch - 4th Generation - won't sync or get recognised by iTunes. I plug it in to the computer and it starts to charge but nothing else happens - please help?

My iPOD Touch - 4th Generation won't sync music and doesn't get recognised by iTunes. I plug it into the computer and the iPod starts to charge but then nothing happens. Usually, when I plugged in my iPod iTunes automatically popped up, but now it doesn't. My iPod has had a WIFI Atenna problem before but I never got it fixed because my iPad connects to the internet fine. I wiped my iPod Touch of memory because I thought that would help but now nothing happens and I need it fixed - please help?

Thanks.