I have an iPod 4G, and i stored music(about 500M) in it. I stored some file(about 2G) in it and deleted the files not long after that, the iPod said there is also 1.5G available?! 4G-500M=1.5G?! and then i format it in windows system, and now i can't get in the iPod system however. It just show an apple logo and don't disconnect, what happened? help, thank you very much.