Here is something I found on Fedora Forum. Try it...
Troubles with AIGLX
the defaults xorg.conf's in FC6 should work, but things don't always work as they should. Here's a few tips that have helped others:
Add these parts to your xorg.conf (/etc/X11/xorg.conf) if you don't already have it:
In your "Device" section:
Option "AddARGBGLXVisuals" "True"
Option "DisableGLXRootClipping" "True"
Just have this somewhere, but not within another Section:
Section "DRI"
Group 0
Mode 0666
EndSection
It seems some of the default fc6 xorg.conf's don't have a "Module" section. If you're missing one, just leave it be like that. It will load the needed modules for AIGLX by default. (This applies to the two next points)
And this in your Module section, if you have a Module section:
If you're using ATi, the following in your "Module" section:
Also try to delete that user & home folder then create a new user. this might solve your problem...