It's one of your USB devices, going over the available power capability of the USB hub. You can find out what it is, and what hub it's plugged into, by looking at the device manager-->under the universal serial devices-->usb root hubs. Look at the properties of each. There is a power tab, and will list what is attached to it (if anything), and the power limit. You may just need to move the device to another set of USB ports.