Setup program can detect available COM ports on my PC but can't 
find out which COM port the PC FM Radio adapter has been
plugged on.

Possible Reasons and Solutions:

1. There is no PC FM Radio adapter plugged onto any COM ports.
   Just simply plug in the PC FM Radio adapter.

2. There is one PC FM Radio adapter on the COM port. However,
   the connection between connectors might be poor. Please pull
   it out and properly plug it in again.