I have had my i pod nano for about 6 months only.i was listening to music on the bus home and everything was fine,wasnt out of battery then about 40mins later i went to put music onto it and it wouldnt turn on or do anythig?!?i have tried swiching it on and off and plugging it in to a usb port to see if that would work but it doesnt even light up Please can you help?????