Windows likes to assign the com ports in sequence, so you need to either pay close attention the first time you plug the dongle in to see which port is assigned or find the com ports in the hardware manager like is done in the video of the previous post. Once a port is assigned to a specific dongle, windows will remember that dongle the next time you plug it in and give it the same port # unless there is a conflict.
You can reassign the port number if desired in the properties window.
Some of the older versions of various software packages did not like port numbers above 8 (I think)...
Of special note: only one program can access the dongle at a time. If you just finished using one program, you have to close it before starting another - for example, you cannot have both the addressing utility and vixen running at the same time. On occasion, I've had to unplug and the reconnect the USB cable on the dongle...
You did install the ftdi driver... Yes?