Ok, so normally the sound on the computer works fine. Then i tried to plug an electronic piano into the computers line in port. I was recording piano pieces using audacity, then suddenly everything stuffed up. The piano doesn't play any sound unless its disconnected from the computer, audacity doesn't register that there IS anything being sent to the computer, and when I try to play any other sound files on the computer, they dont work. But all works again when i unplug the piano. Nothing is muted, volume is up to max. ?