How to re-install grub???

How to re-install grub???--------------------------------------- 1.  First find the partition which contains the /boot directory grub> find  /boot/grub/stage1   (hd0,4)  or, grub> find  /grub/stage1   (hd0,4)  2.  Execute the root command to find "/boot" partition grub> root   (hd0,4) grub> root (hd0,4)  Filesystem is type ext2fs, partition type 0x83 3.  Lets re-install Grub to a partition boot sector grub> setup  (hd0,4) 4. Now restart the server- grub> reboot 5....