Hi! Sorry for the (possibly) stupid question - I have a fourth generation ipod nano that spontaneously died - black screen, will not turn on. When plugged into a power source, it works fine, it says the battery is fully charged, I can scroll through my playlists while plugged into a dock - but as soon as I unplug it, it turns off and and refuses to respond no matter how hard I hit it (kidding - but it will not reset when I hold down the menu and select buttons). Is the battery dead for sure? I've had it eighteen months but didn't use it that often (mainly at the gym, so not often at all...) I've also tried restoring it with no effect. Thank you in advance for any advice.