My camera is taking black pictures, how do I fix it?

I realized that my canon S3 IS is only taking black images no matter what I do, I point it at the scene I want it to capture but I cannot see it on the screen or when I try and see the photo, all I see is black!? I was pretty suprised when I saw that what I wanted to capture was black not just the photo but the camera its self can't capture the photo...I was curious if i could do anything to fix it or if I had to take it in to get it repaired?