Gnome freeze at startup

Hi,
Since the last system upgrade, the network card is not detected at boot and gnome is frozeen at startup.
I fixed the network card problem by adding the driver to the module list loaded while booting.
I have rebuild all the system and gnome still frozen. I have no error message in Xorg.0.log.
Is it a problem with kernel 3.6.7 ?
I install kernel 3.6.11 and 3.5.7 and nothing change.
Thanks

I have rebuild all packages and all is ok now.