My PC is displaying some VERY nasty tendencies when I listen to my headphones. After the power supply blew up in the old PC, I have had to change some gear. I have an MSI mainboard with a built in POS 5.1 audiocard. Connected to that is a dinky logitech 5.1 speaker pc system. I plug my sennheisers into the headphone socket on this unit. Before changing to the MSI board, no problems. Now, static comes through the cans which can only be heard when it's quiet but is still there. Is it the board or a wiring issue? Perhaps the powersupply?