My ipod is either 4th or 5th gen. It started to have problems before it stopped working at all. First the backlight was always off. Then the screen went black. Then tge hold button didnt work properly. It would be on vut thedial would turn and work. Then the music stopped playing out the speaker and then the headphones. Now it wont charge or turn on or do anything really. What's wrong with it? I dont want a new one and i want all the music that's in it. Can i fix it without erasing the music?