What software version is the SX20 running?
If running TC software, could they be in the camera control menu, which will allow them to move the camera?
What if they hit the Home button and try to navigate through the menus?
If it appears that no matter what you try, you can only control the camera and not get into the menus themselves, there could be a faulty connection between the camera and codec, or one of the camera ports have gone bad. At this point, you'd want to swap the camera with another one to see if if the camera or the codec is the issue.
