If ^^that doesn't bring up any new hardware, expand the universal serial bus controllers, right click on the usb root hubs, and click the power tab. You can see what is attached at each hub. Find the one that has the dongle/unknown device, right click and uninstall it. Then restart the computer.
If none of the usb root hubs show the device, then uninstall all of the usb root hubs, and restart.