I know this is a stupid suggestion, but there is a check box for enabling touch capture in the camera settings, check it.
and about the settings, I usually shoot in auto, normally I shoot around 5 photos of what ever is there, touching different areas on the screen (because it changes all the auto settings depending on the color and brightness of the place you touched), then pick the best shot, the only manual tinkering that I do is choose a scene mode.