I have my Wii hooked up to the direct inputs on my z-680 speakers. The coax is plugged into my pc. Whenever the coax cable is plugged into the pc, I get a white line that moves up the screen when TV is on appropriate video channel for the Wii. When the coax is hooked up to the dvd player, or nothing at all, no problem, only on my coax output on my pc. Anyone heard of this before? Could it be some sort of noise coming from the pc?