You need to go into device manager in control panel. In the list you'll see the USB lead listed as a virtual serial device. Go into the properties of it and change the COM port to COM3. You may need to restart after. When it's restarted then open vag com and set the usb lead to run from COM3. Although the lead is USB, the drivers make the laptop recognise it as a serial cable hence listing it as a virtual serial device.