Xbox 360 wired control pad won't work
Possible fix, make sure your contacts are clean, and your cable is not damaged. Obviously the 5v lines are connecting, but no data is getting through. I reccomend using a q-tip to get any grime off, but you may need rubbing alchohol (90% reccomended because it dries cleaner). Clean off the connections on the xbox and the controller. If it still doesnt work, list any extras you have plugged into your controller, and the estimated time you bought the controller.
If all else fails, I've just got a great deal on a MadCatz xbox 360 controller ($25) and its fully functional, minus the controller faceplates if thats your cup-o-tea.