Help, I Lost MyDesktop!

I spilled on my keyboard and after cleaning up I found that all graphics on my desktop are missing. Im guessing that while wiping I hit a key (or keys) to cause this, but I dont know how to restolve it. I would like to either restore my desktop or restore my computer to an earlier date, but I have no start button to access these options. Also, nothing happens when I right click the desktop. Any suggestions?
Kathy