My Ipod Classic keeps saying connect to power, but it's already plugged in and it won't charge.

I haven't used it in a while so it's been dead for a little bit. I tried charging it but it keeps saying connect to power. I don't know what happened. Do I have to buy a new Ipod? It's only two years old. I've only dropped it once but that is when I first got it and it worked completely fine till now. It just won't charge. I have tried different chords and different charger outlet things but it doesn't do anything. What do I do?