help with fighting video 1 and S-video on Advent TV Q328

I need help. my Video 1 and S-video pictures are fighting eachother which means i can not see any picture that is pluged into video 1, S-video, or video 2. all i have is a blue screen and sound that is coming from the sound system. I have tried unpluging the S-video but it does not help. I have even run the cable straight to the TV but that does not help. Any help out there? Thanks so much!