I have a 3rd Gen. iPod which originally came with an AC Charger which had a firewire cable that connected to the charger. I have misplaced the charger, so I purchased a charger that has a USB 2.0 cable that connects to the charger. The charger will not charge my iPod. The charger is working as I pluged it into a newer model iPod and it charges. I borrowed a charger, like my original charger(firewire cable) and the battery charges. If I plug the USB cable into my computer, the iPod is recognized, but the computer will not charge the iPod battery. Any answers???