I have Logitech z506 5.1 surround sound speakers and when I plug them into my pc line in port. All my speakers work except my center speaker which if I unplug my speakers from my power and restart my pc it will work but after a while, it will stop playing audio again. How do I get all of my speakers to work at the same time again? If I plug my center speaker into a different port it will work all the time.