Q: Why would my iPod freeze up and not be able to work even when connected to my computer??

I was listening to new songs I had downloaded last week and when a song finished it went black.  You can see there isthat song up on the screen, but it is black and not responding.  I have plugged the iPod into my computer and it is not responding as well.  iTunes says there is no device connected.  Help, please.  Thank you.