i have upgraded Ubuntu desktop from 12.10 to 13.04. Since then I can't see the Panel or Launcher, but I'm able to open the terminal using the keyboard shortcut Ctrl+Alt+T.
When I use the Guest login there is no such problem. I am facing the problem only with administrator account. I have tried this Launcher, top Panel, and window decorations missing after 12.04 upgrade, but I couldn't find the result.