Lucid: only wallpaper after login, no panels, no right-click menu

[Juan R. de Silva]

I've upgraded from 8.04 to 10.04, not without problems but all was fixed 
and run OK.

Today I logged in as another user to configure his desktop. By mistake in 
the Add to Panel applet I selected the Switch User applet already added 
to a Panel and hit Add button again.

The Switch User applet crashed immediately. I get an Error dialog box 
notifying of a problem and prompting either Delete or Reload the crashed 
applet. I selected Reload, and the Switch User applet was restored to its 
position. So far so good. 

I completed session, logged out, get to the Login dialog box and logged 
in myself... Here were the bad problem showed up.

All I have after login is my desktop wallpaper displayed. No panels. No 
reaction on the mouse right-click. Nothing. Plain dead desktop.

I can switch to one of the tty's via Ctrl-Alt-Fx. Thus my keyboard is 
alive. I tried to run "status gdm" and get "gdm start/running, process 980
" in response.

The second user is fine and can login/logout at any time.

Any idea how to fix it, folks? I could not come up with a good enough 
keyword/phrase, so Google was not in much help so far.