Start terminal/powershell as an administrator and run:
(Replace :5432 port number with the one you want to free, e.g. :8080)
This way you can see if the port is busy:
The last number (here 6740) is the Process ID (PID). Use it to kill this process and free the port:
(Replace 6740 with PID from the command above)
The job is done. Continue coding like you've never been hurt before.