my iPod U2 4th gen started acting up on me. it needed to be reset more and more often, until it decided to just stop working all together. it would show me the apple sign, sad face, and low battery symbols. bought and installed new battery, won't charge. it changes from apple icon to sad face back and forth on it's on when plugged into wall with firewire. goes from apple icon to sad face when connected to pc via USB. pc won't recognize it. please help! i've tried everything! is there something wrong with my hard drive? i'll pay anything to save the files on my hard drive. HELP!!!!!