desktop icons move to Right side of screen


I usually have the desktop icons arranged by app/custom arranged by me. They used to always stay that way but suddenly they have moved to the right side of the screen (almost exactly by 50%) only Photoshop Elements doesn't move. I have looked at rearranging them via 'arrange by'...none of the choices seems to 'keep' the arrangement chosen and at the next bootup the icons have moved again.
What is going on?