[Novalug] Ubuntu 8.04 - wallpaper and desktop items have disappeared

[Jim Ide]

I am using Ubuntu 8.04.

I was fiddling around with changing wallpaper, and I have broken
the desktop somehow.  When I log in, none of the items on my desktop
are visible, and no wallpaper is displayed.  The files and directories
are still present, but they are not being displayed on the desktop.

If I select System | Preferences | Appearance from the menu, the
Appearance Preference window opens for a half-second and then
closes before I can see or change anything.

Any ideas about how to fix this?

Thanks.