Reinstall Grub 2 in Fedora 17
Grub 2 is the latest version of Grub. Its still in beta but despite thatl it ships with the most popular linux distros like Ubuntu, Fedora etc.
If you have installed Fedora 17 but some how grub got messed up and you are unable to boot in to Fedora 17 then follow these steps to Restore or Reinstall Grub 2 in Fedora 17.
Boot from the Fedora 17 DVD or Live CD or may be you used USB to install Feodra 17, use any methode just boot using any Fedora 17 media.
Select Troubleshoot from the boot menu and then select "Rescue installed system"
When in Terminal execute these commands.
chroot /mnt/sysimage grub2-install /dev/sda grub2-mkconfig -o /boot/grub2/grub.cfg
Now reboot your pc and Fedora 17 should boot. Remember this will replace your existing bootloader, but you can always add more entries in Grub.