The main panel, the one with the menu button, quick launch, etc. has dissapeared and nothing I do seems to bring it back. I renamed .kde4 to .kde4.old and restarted the window manager and it's still missing.
I created a new user and everything is there and working.
I guess my question is how to restore the panel when it goes south?

Which version? In newer versions you can do like this to add a new default panel.

Hi and thanks for the tip.
The version is KDE4.x, probably one of the newest releases as I've had my friend update her PClos several times since I installed it. I can't get my hands on the PC as she's a couple of hundred miles away now and I don't think she is savvy enough to set up remote desktop yet.
Any idea why the default panel would dissappear? I'd like to prevent it from happening again if possible.

I have the same problem and its not the first time. I've seen this in different machines.

Main panel disappears, and plasma "corner" also disappeared so I'm unable to create new panels. I can only use desktop icons.

Removing ~/.kde4 and restarting session does not fix the problem, but on a new user account everything works fine.

The solution is to manually run /usr/bin/plasma-desktop and everything loads but I don't know how to do it automatically again.