I have a 3rd Gen. 10 gig iPod. I can't get it to charge with a new charger that has USB 2.0 cable supplied with charger. Original charger/cable was firewire. Manual claims that either will work. Charger is OK as it works on a newer model ipod. When battery is charged, PC recognizes the iPod when connected with USB cable, but will not charge thru PC. Any answers???