Sound trouble on Epson Moviemate Projector

I have a epson moviemate projector with a built-in dvd player. It also has the capability to play presentations from a PC. Suddenly, the audio from my PC will not play through my projector. I ran a line from the PC to the microphone jack on the projector and that solved the problem…Once. It has not worked since. Have I damaged the projector, blown a circuit, or has something been inadvertently turned off in the audio portion of the projector?