I have a first gen nano, that has served me well for several years that I bout off of ebay. Yesterday I charged it and it finished, just like it always has, and it worked fine until, this morning I went to turn it on to listen to music, kand there is absolutely no response. I tried plugging it in to my apple wall charger, and I tried plugging it in to my mac. There is still no luck. Is the battery dead?