I had the same problem here. For some reason the update caused some mismatch between the kernel and nvidia drivers. First check that your problem is the same as mine. If you entry
cat /var/log/Xorg.0.log | grep EE
[ 30.666] (EE) NVIDIA(0): Failed to initialize the NVIDIA kernel module. Please see the
[ 30.666] (EE) NVIDIA(0): system's kernel log for additional error messages and
[ 30.666] (EE) NVIDIA(0): consult the NVIDIA README for details.
[ 30.666] (EE) NVIDIA(0): *** Aborting ***
[ 30.666] (EE) Screen(s) found, but none have a usable configuration.
If you then entry:
[ 31.051609] NVRM: API mismatch: the client has the version 295.59, but
[ 31.051610] NVRM: this kernel module has the version 295.40. Please
[ 31.051611] NVRM: make sure that this kernel module and all NVIDIA driver
[ 31.051612] NVRM: components have the same version.
To fix that first check which kernel version you are running and which are available for you at /boot
I was running on 3.3.2-6 and should be 3.4.6-1, for the nvidia driver to work. The problem was that there where no option, at boot time, to select the newest version of the kernel so I had to run grub2-mkconfig again.
sudo cp /boot/grub2/grub.cfg /boot/grub2/grub.cfg.bkp
sudo grub2-mkconfig -o /boot/grub2/grub.cfg
After that I was able to select the newest version of the kernel and it worked nicely. In case this still don't work you may have to reinstall the drivers and xorg to update the configuration.
sudo yum reinstall kmod-nvidia-PAE.i686 xorg-x11-drv-nvidia.i686 xorg-x11-drv-nvidia-libs.i686