Since the Fedora 5 release is not compatible with third party 3D graphics acceleration
drivers, You should immediately update your Kernel upon installation to get a newer
Kernel that is compatible
Checkout this link for the solution:
*stanton-finley.net/fedora_core_5_installation_notes.html#nVidia
Also read this (what RedHat has to say about proprietary Video driver( ATI, NVidia, etc.,):
*www.redhat.com/archives/fedora-test-list/2006-February/msg01565.html