You have to add the GPS to your Bluetooth stack before it will provide a COM port that your navigation software can find. This usually involves clicking on the Bluetooth icon in the notification area (bottom right of the screen) and choosing 'Add a Device'. With your GPS in BT mode, the BT stack will discover it and ask for a code (0000).Then it will set up a COM port that will provide the serial output point that your navigation software can derive the GPS data from.
Terry