Simply remove the computer from the power supply. If it! Note that this does not mean simply rotating equipment using the power button because most modern computers do not close completely and the motherboard will always get power. Sometimes it is useful if you want to enable remote to the computer, etc.
the motherboard is connected to the computer equipment, including a USB port. Sometimes the motherboard needs "reset" because things can go wrong, that some or all of the USB ports suddenly stop working. small microprocessor motherboard recharge USB port driver and expectations should recognize the device again.
So stop your computer using Windows UNEMPLOYMENT first selection or pressing the power button and remove the PC from the network. Let stand for a few minutes, then reconnect.