gdmgreeter refuses to start in fc7

After I convinced my wife to use Linux and three days of satisfied use of fc7, today it seems  the gdm greeter refuses to start... ;-(
I'm not at the PC but I connected remotely.
She says that at the screen she gets "the greeter refused to start, retry...". If she presses ok the same happens.
Already tried to restart but the same...

In messages I have:
Jul  3 14:40:34 localhost gdmgreeter[3129]: The accessibility registry was not found.
Jul  3 14:40:38 localhost gdm[3025]: failsafe dialog failed (inhibitions: 0 0)
Jul  3 14:40:38 localhost gdm[3025]: failsafe dialog failed (inhibitions: 0 1)
Jul  3 14:40:57 localhost gdmgreeter[3180]: The accessibility registry was not found.
Jul  3 14:41:02 localhost gdm[3025]: failsafe dialog failed (inhibitions: 0 0)
Jul  3 14:41:02 localhost gdm[3025]: failsafe dialog failed (inhibitions: 0 1)


Strange is that
 [root@localhost log]# ps -ef|grep -E "X|gdm" | grep -v grep
gives:
root      1733     1  0 14:39 ?        00:00:00 /sbin/mount.ntfs-3g /dev/sda1 /XP -o rw,nls=utf8
root      3025     1  0 14:40 ?        00:00:00 /usr/sbin/gdm-binary -nodaemon
root      3107     1  0 14:40 ?        00:00:00 /usr/sbin/gdm-binary -nodaemon
root      3185  3025  0 14:40 ?        00:00:00 /usr/sbin/gdm-binary -nodaemon
root      3187  3185  0 14:40 tty7     00:00:01 /usr/bin/Xorg :0 -br -audit 0 -auth /var/gdm/:0.Xauth -nolisten tcp vt7
gdm       3205  3185  0 14:41 ?        00:00:00 /usr/sbin/gdm-binary -nodaemon
gdm       3208  3025  0 14:41 ?        00:00:00 /usr/sbin/gdm-binary -nodaemon

yesterday I used without problems the system that is an x86_64 updated fc7.
I updated several not apparently related packages:
In yum.log I have:
Jul 02 23:31:52 Updated: xvidcore.x86_64 1.1.3-1.lvn7
Jul 02 23:31:53 Updated: livna-config-display.noarch 0.0.14a-1.lvn7
Jul 02 23:31:53 Updated: k3b-extras-nonfree.x86_64 1.0.2-1.lvn7

then I manually installed these:
Jul 03 00:54:33 Installed: xmlrpc-c.x86_64 1.06.11-2.fc7
Jul 03 00:54:36 Installed: cmake.x86_64 2.4.6-3.fc7

Strange to say, yesterday I was proposed to upgrade gnome-menus to 2.19.4 but I deselected it
It seems strange as this should be a devel package not in mainstream fc7, or not?

After the problem today I tried to upgrade it
Jul 03 14:37:49 Updated: gnome-menus.x86_64 2.19.4-1.fc7

But nothing changes...
In its changelog I can misteriously see:
* Sun Jun 17 2007 Colin Walters <walters@xxxxxxxxxx > - 2.19.4-1
- Update to 2.19.4

* Tue May 29 2007 Matthias Clasen <mclasen@xxxxxxxxxx> - 2.18.2-1
- Update to 2.18.2
???

In /var/log/gdm I have:

[root@localhost gdm]# ls -lrt
total 32
-rw-r--r-- 1 root root 793 2007-04-27 22:59 : 20.log.2
-rw-r--r-- 1 root root 791 2007-05-16 22:05 :20.log.1
-rw-r--r-- 1 root root 888 2007-06-14 18:47 :20.log
-rw-r--r-- 1 root root 792 2007-07-03 14:19 :0.log.4
-rw-r--r-- 1 root root 792 2007-07-03 14:40 : 0.log.3
-rw-r--r-- 1 root root 879 2007-07-03 14:40 :0.log.2
-rw-r--r-- 1 root root 792 2007-07-03 14:40 :0.log.1
-rw-r--r-- 1 root root 792 2007-07-03 14:40 :0.log

In :0.log
X Window System Version 1.3.0
Release Date: 19 April 2007
X Protocol Version 11, Revision 0, Release 1.3
Build Operating System: Fedora Core 7 Red Hat, Inc.
Current Operating System: Linux localhost.localdomain 2.6.21-1.3228.fc7 #1 SMP Tue Jun 12 14:56:37 ED
T 2007 x86_64
Build Date: 11 June 2007
Build ID: xorg-x11-server 1.3.0.0-9.fc7
        Before reporting problems, check http://wiki.x.org
        to make sure that you have the latest version.
Module Loader present
Markers: (--) probed, (**) from config file, (==) default setting,
        (++) from command line, (!!) notice, (II) informational,
        (WW) warning, (EE) error, (NI) not implemented, (??) unknown.
(==) Log file: "/var/log/Xorg.0.log", Time: Tue Jul  3 14:40:59 2007
(==) Using config file: "/etc/X11/xorg.conf"
(II) Module already built-in

In :0.log.2 I have this line more:
AUDIT: Tue Jul  3 14:40:51 2007: 3136 Xorg: client 2 rejected from local host (uid 42)
Anyone experiencing this?
If I set KDE as desktop manager in /etc/sysconfig/desktop file, I get the kdm login screen, but trying to connect I get again the login screen and in messages:

Jul  3 15:19:45 localhost kdm_greet[5331]: Internal error: memory corruption detected
Jul  3 15:19:45 localhost kdm: :0[5355]: Can't execute "/usr/share/config/kdm/XstartupI renamed them as Xreset and Xstartup but nothing changes
If I set XDM in /etc/sysconfig/desktop I get the xdm login and I'm able to log in with a primitive X session.... ;-)

Also, doing a startx from init3 I get correctly a root X Windows session....
rpm -vV gdm
gives no errors....
Can anyone point to a solution?
Thanks in advance,
Gianluca