How to re-install MBR for the Boot into Linux

If you MBR ( Master Boot Record ) is corrpted , you are unable to boot into Linux. Then you have to restore the GRUB boot loader.
To do this, you need a linux distribution CD. If you are using Redhat , fedora CD version then you only need first CD . But you may also use any af the live CD's like Ubuntu , Redhat and so on.

Then you boot your PC using first CD of Fedora, and enter the following command at the installation boot prompt
( installation boot prompt == after booting cd , first stop window)

1. boot: linux rescue
    .... Press enter , after press enter you have to select " language , type of keyboard ,      
   how to boot like  network boot or  not"

2. # chroot /mnt/sysimage
   

3. # grub-install /dev/hda
   NOTE : If you have an IDE harddisk "/dev/hda" ,
                    If you have a SCSI harddisk (Sata) "/dev/sda".

4. # exit

5. # reboot
   

Now you can boot your Linux OS...............