some images are corrupted

some images are corrupted

can anyone advise.. I take a series of photos. every so often the message on the camera says 'unidentified image' . on the computer these images are completely scrambled, like cut into random pieces and reassembled irregularly. But only on some of them, the others are fine. I'm about to dismantle the whole camera as the lens is stuck and need to know whether and what I should replace while I'm at it. Thanks..