Jonathan Ayoub, the first thing I would do after I did all the things that you did, and hoping you did not drop it or anything like that, is to check your dock connector as well, make sure you do not have any broken, bend or corroded pins. You can also try a new USB cable. If none of that should work, change the battery. change the battery. This would give you a clean starting point. You can also try to charge the iPod on an AC charger and see what it does. Good Luck and let us know how it is going.
[guide|1131]