Check device manager under ports when you have your device unplugged probably only COM1 there.

Plug in device and refresh device manager (F5) there should now be a extra COM port.

COM4 is given as the example.   1, 2, 3, 4 and COM 1 , COM 2 etc won't work either.

So COM(no space)(number).

Also unplugging the jumper from the side (so the back light is off will give a better chance it's detected in the computer.

If that fails try install the driver from folder 1. In v1.7

Let me know how it goes.