Ixus 500 image quality?

I have an old Canon IXUS 500 camera which I use for diving and quick holiday snaps - when I went to use it recently the camera seemed to take the photo ok, but the picture on the LED screen came out extremely distorted.

I had hoped that the LED screen was at fault, but when I went to download the photos, the downloaded photos were also distorted. Is this a common problem and does anyone have any idea as to how to cure it.
I think it could be an exposure problem. All help gratefully received