Restore grub

Sometimes, you may mess up with your grub and you can not even boot up your system because of the broken grub.

Here is a simple way to restore or re-setup grub.

1. Boot up your system with the first install CD or DVD to go to the rescue mode (e.g., linux rescue)
2. Let the rescue mode mount your linux partition(your root(/) partition) to /mnt/sysimage.
3. chroot /mnt/sysimage
4. grub-install /dev/hda ⇐ if your grub is not installed/messed up, try to reinstall it
5. grub
6. root (hd0,1) ⇐ The first number indicates the disk and second one is for the boot partition
7. setup (hd0)
8. quit
9. And get out of the rescue mode and then boot up your system without your installation CD / DVD