Backup your /etc/X11/xorg.conf file (eg. cp /etc/X11/xorg.conf /etc/X11/xorg.conf.orig) and then delete /etc/X11/xorg.conf (rm /etc/X11/xorg.conf)
Now remove all nvidia drivers :-
1. First find them all with rpm -qa|grep -i nvidia
(I get the following when I run this command
xorg-x11-drv-nvidia-libs-173.14.12-1.lvn9.i386
kmod-nvidia-2.6.26.5-45.fc9.i686-173.14.12-5.lvn9.i686
kmod-nvidia-2.6.26.6-79.fc9.i686-173.14.12-5.lvn9.1.i686
kmod-nvidia-2.6.26.3-29.fc9.i686-173.14.12-4.lvn9.i686
xorg-x11-drv-nvidia-173.14.12-1.lvn9.i386
kmod-nvidia-173.14.12-5.lvn9.1.i686 )
2. Remove all instances by using rpm -e xorg-x11-drv-nvidia-libs-173.14.12-1.lvn9.i386 kmod-nvidia-2.6.26.5-45.fc9.i686-173.14.12-5.lvn9.i686 kmod-nvidia-2.6.26.6-79.fc9.i686-173.14.12-5.lvn9.1.i686 kmod-nvidia-2.6.26.3-29.fc9.i686-173.14.12-4.lvn9.i686 etc etc ie. put all of your install nvidia stuff on the one line after the rpm -e command
3. reboot your computer. This should boot to an X server using the open source "nv" driver.
4. If this does not work, I would replace the "vesa" with "nv" in your original xorg.conf file and try rebooting again.
To see if the nvidia graphics chip is being recognized you can run the following command "/sbin/lspci". This will list all your pci devices and with any luck your nvidia graphics card will be listed. The output for this command for my card is :-
01:00.0 VGA compatible controller: nVidia Corporation GeForce 8400M GS (rev a1)
Here is a post regarding the new card you have which may give you some help
http://forums.fedoraforum.org/showthread.php?t=197275
Good luck