It seems like your Kinect is competing with other devices on the USB bus. Just FYI, Kinects uses a lot of USB bandwidth, so switch to another unused USB root hub. You may need to purchase a PCI-E USB expansion if you don’t have enough root hubs.
EDIT: Switch around USB ports until it works essentially. If your PC’s front panel (or laptop’s side panel) have a bunch of USB ports, connect there. Make sure there is nothing else connected to the remaining USB 2.0 ports.