I have one major problem with my CS5. When I open a any file (TIFF, PNG, JPEG), I can only see the actual image if I have the zoom value set at 25%, 50%, or 100%. If the zoom value is set to ANY other value, the image disappears and all I see is the checkerboard pattern;however, I do still see the image in the layers panel on the side of the screen. Any idea why this would happen???