nope. you don't need to reinstall fedora as of now... try:
rpm -qa |grep <kernel source name>
this will show whether the package by this name exits...
now, if it exists... rpm -e <kernel source name>
if it shows any dependency problem, then remove that package first...
also, you can type.. rpm -e <kernel source name> --nodeps
to ignore dependency issues. be WARNED that is Dangerous...
next, mount the cd that has the source rpm and then,
rpm -ivh <kernel source name>
next , after successful install of the kernel source, goto ctrl-alt-F1. there log in as root
next type -> init 3
now, press ctrl-alt-F7 to clarify that XServer is not running..
now.. if you have the default kernel provided by fedora, then type,
//NOTE: without this installer may give error.. as there is GCC3.3 present in fedora and the default kernel has been compiled using GCC3.2
from the directory where the installer is there...
next.. modify the /etc/X11/XF86Config file to have
Option "nologo" //<NOTE>this is optional if you don't want NVidia logo
now, type.... init 5
your XServer should start...
ATB, keep posted with the results..