Today, out of the blue, Illustrator stopped displaying any raster images. The file opens, but I just get a blank artboard. The title bar at the top of the page shows the preview but it doesn't display on the page. It doesn't seem to matter if I import the file or if I just open the file straight into Illustrator. I've tried PSD, JPEG, TIFF, and PNG without success. This morning I was redrawing old logos for a client, and this afternoon I can't open anything that is rasterized.