my original usb charger was working perfectly fine! and all of a sudden it stopped working and a message saying Because a USB device was drawing too much power from your computer, one or more of your USB devices have been disabled keeps coming up! i then tried to use the wall plug and it doesnt work any more! the usb cable doesnt work at all now! i bought a new usb cable and connected it to my mac and it worked fine and then the same thing happened again. i tried to charge it with the plug and once again the usb doesnt work at all! i borrowed an iphone charger and it works fine! i also have an iphone 4 and i dont have a problem with it! its just my iphone 5!!