That would suggest the usb is either exceeded bandwith or there is a problem with your adapter (happened to me once, the light came on but the usb cable was damaged,i had to replace the adapter).
Things to try-
Hook your kinect up to an xbox 360 to make sure its not damaged.
If not then its the adapter or the usb bandwith.
Try a different usb hub, and try again, remove all other usb items to test.
If it works then you know its usb bandwith – one solution is to buy a powered usb hub.
If it doesnt work then replace the adapter, they are relitavely cheap on amazon and ebay.
Good luck