Rubber banding in Autocad

I must have hit the wrong key because suddenly I can't see the "rubber band" effect when doing rectangles, circles and arcs. This is annoying, particularly for free form arcs because I can no longer see the arc until I click it into position. Did I alter some system variable to do this? How to correct it? Also, does anyone know how to import XREF's and render them with their original materials? Thanks, Kerry