Desktop empty

I have a Ubuntu 9.04 , It has been working fine, I decided to change my desktop background and put a picture and change the theme. To apply the changes I restarted the computer, the picture appears with an empty desktop no taskbar and toolbar which was at the top, the clock, the icons, firefox, evolution email, etc.
all gone, I am lost can you help?

try this in terminal to

try this in terminal to restore the panels

$ gconftool-2 --shutdown
$ rm -rf ~/.gconf/apps/panel
$ pkill gnome-panel

sorry my english