I have just bought an iPod Touch second hand. I tried to update it's firmware to the latest version using iTunes. The update failed and now I cannot access the iPod either directly or in iTunes. Turning the iPod ON the screen shows a 'connect to iTunes' looking icon and does nothing else. Connecting the USB does nothing and the iPod does not show up in the iTunes side bar. The iPod turns itself OFF after a minute or two. What now?