Leopard software update mayhem. Help!

Ok, so I upgaded to Leopard a few weeks ago. Today I tried to do a software update that included iLife, iTunes, and a couple other updates. The update stalled a quarter of the way through. Now, my hard drive icon, all of the folders on my desktop are gone, and the tool bar at the top of my screenis gone, unless I open an application, (if it opens at all) in which case it becomes the normal opaque white. Disappears again after I close the application. The computer also keeps trying to index my backup drive. I can't send messages on iChat, iCal won't work, and my disk utility is not working properly. I have tried to run software update again but it will not work. Any ideas?