Hi folks,

> It also gives a segmentation fault in usr/sbin/gdm

If I'm not completely off-track, gdm is the Gnome display manager, running independently from user settings (it's the process "driving" the X servers and eventually starting some login widget). As that is already crashing with a segmentation violation, something more general seems to be broken.

In order to rule out broken files (i.e. by some partial hard disk failure), I recommend to run
# rpm -Va
to test the integrity of all installed RPMs. There of course will be differences reported - i.e. configuration files. But if some lib or other "binary" is reported as modified, please run a forced reinstall of the corresponding RPM.