Have you tried it in different ports? If you have it in a front port, try it in a rear port or vice versa. Depending on your computer it is entirely possible that the different ports have different amounts of power available to them to give to whatever is plugged in. Also if you have USB 3 ports (blue ones) try those as although your controller probably isn't USB 3, the ports themselves should be able to give more power than a standard USB 2 port (if it is a power issue...)