Hi and welcome to LQ.
If you have the Fedora installation DVD or Rescue Disc, you can boot into rescue mode and reinstall Grub. This article explains
how to boot into rescue mode. When you see the command prompt after booting into rescue mode, run "grub-install /dev/hdx" and if thats successful, reboot. Replace hdx with the actual device name of the dirve where grub is installed e.g. /dev/hda.