Monitor thinks it is in tv mode when S-video hooked up

I think I screwed up the initial setup and the when the S-video is hooked
the monitor show an empty dessktop. No mouse cursor, taskbar or icons. When
I disconnect the s-video and restart the monitor then displays the desktop
and works normally.

I haven't actually looked at the tv yet as it's in another room. Even if the
desktop is on it I don't want to be jumping from room to room to manipualte
the screen.

Any ideas?