Got this problem a few weeks ago:
A guy had just bought a new Vista machine (HP 8000N) and took it home happy as can be. A few days later he experiences a problem. Vista was displaying about half his image thumbnails in a horizontal strip. We were both quite confused for a while, especially since MS Paint loaded the images correctly.
So I imported the images into the GIMP (free image-editing program) and re-saved them. Lo and behold the images displayed correctly. So I pretty much deduced that the camera was writing the images incorrectly (which I have never heard of before.)
A week or so later he comes up to me and says all the "broken" images were from one camera.
What do ya know.
(Didn't catch the model of the camera.)