I have it installed, but when I try to activate it (by running nvidia-xconfig as root) the X server doesn't work again after restart,
I wonder, did you re-install the nvidia-173xxx package after the upgrade to fedora14?
To save my self some time I use the vesa driver untill I have the kernel ready for the nvidia module is installed.
Then after I install the nvidia package I edit /etc/X11/xorg.conf.
Changing just the one line, vesa to nvidia.
I also install the nvidia package from cli, type init 3
to shutdown the gui.
does the command glxinfo give you anything?
glxinfo | grep render
I also have trouble using the nouveau module.
Have you thought of installing the nVidia *.run ?