can login in gnome only with failsafe

[Godfrey]

Hi,

When I try to login, I only get a brown screen with nothing on it
except the pointer, moving the mouse will move the pointer. There is
no pannels at the top, neither at the bottom of the screen.
Crl+Alt+Backspace kill the brown screen and bring back to the GDM
login screen.  Then when I click on Session, and choose "failsafe on
Gnome", I can login with the panels, and gnome works fine.  So I
cannot login gnome normally anymore.  I have no problem before, now I
can only login with "failsafe".  Any idea?