serial port for MindWave in Windows8.1

Question

How can I find what is the serial port assigned to the MindWave USB in Windows8.1? The code I am using has this for Mac OSX:

import platform
import sys, time
from mindwave import bluetooth_headset
import httplib, urllib, urllib2
import json

#serial_port = '/dev/tty.MindWaveMobile-DevA-10'

Here's what my device manager shows:

I'd like to know how to change line 10 of http://pastebin.com/jR21F4Xf in order to make it work in Windows. Currently MindWave USB Dongle is connected to COM4.

Here's the config file:

{
    "mindwave_serial_port": "COM4",
    "hue_bridge_addr": "10.0.0.225",
    "user": "mona6_000",
    "send_to_gatd": "True",
    "show_spectrum": "True"
}

Here's what MindWave Manager shows:

Here's what I get in PowerShell:

I have installed pyserial using easy_install:

However I cannot import it in python interactive shell while I don't get any error running my code: