I think your PC needs some work.
What shows up in Device Manager? Does the USB to Serial dongle appear in under Ports (COM & LPT)? What new serial port number shows up?
Again if you have any Bluetooth devices that create virtual Com Ports, it will take the loader a while to determine which ports are active. The program will almost freeze while it waits for Windows to report this information to the Loader software.
Please don't expect the loader software to find the Com Port if Windows (which provides access to the Com Port for the loader) doesn't recognize it first.
Below is a screenshot from the software of where the serail port setting is located. Sorry but the computer I am currently using only has one physical serail port (COM 1) and I don't have any other ports to demonstrate how this list can be populated.
When i get access to my laptop, I will post a new picture with a more complex array of Com Port options.