I know the solution for this issue. Go to your command prompt by just clicking on your Start and then typing cmd. In your command window you need to type in the below command:
netstat -a -n -o
In above command the -o parameter is used to add the PID to the end of a table. On pressing enter and you should see the active connections along with the PID.
Now you need to see the name of your process that is still using your port so you must go to Task Manager by simply pressing CTRL + SHIFT + ESC and then try to click on a Process tab.
Your task manager will not display the process ID by default so now you must click on View and then try to Select Columns.
If you want to look into services which are running in background then simply right-click and select the open services. Then you can take the required action on that service.
Hope it fixes your issue.