Not sure how or when this happened BUT while in system preferences when I click on DESKTOP/SCREENSAVER or SPACES/EXPOSE icon, the box is white with no options or text. All the other preferences work but these two. I can click between "show all" and desktop/screensaver and after 3 tries, the screensaver side shows up with ONLY the left column, not the right. And if I click on the Desktop tab, I get a blank screen. I have repaired permissions and rebooted but to no avail. How would I know if these 2 prefs are corrupt AND where would I get a working copy of them?