Fedora 9 had been working fine for me for months. Now, though, when I start or restart I always get this message:

There was an error starting the GNOME Settings Daemon.

Some things, such as themes, sounds, or background settings may not work correctly.

The last error message was:

Launch helper exited with unknown return code 0

GNOME will still try to restart the Settings Daemon next time you log in.

And more problematically, the gnome taskbar is gone and I can't seem to get it back. I had recently installed totem-gstreamer, so I uninstalled it, but the problem persists. I cannot think of any other recent changes that would cause this. Can anyone offer some advice?

(Though they are probably unrelated, two other recent problems are that package updates have not been working lately and my MyBook external hard drive, which had been recognized automatically, is no longer recognized by Fedora. If it were, I think I would just back everything up and reinstall Fedora or even move to Ubuntu.)


Edit: Another clue. A new problem is that I cannot start firefox, but get this output in the terminal...

[carl@localhost ~]$ firefox
Could not find compatible GRE between version 1.9b5 and 1.9b5.

Is it clear to anyone what has gone wrong with my computer?