The Linux Society

When many first time users are installing linux in a dual boot configuration. they may not realise, windows must be installed first as it does not recognize linux and will overwrite the grub boot loader or some other occurence that erased/changed your MBR so that grub no longer appears at start up or it returns an error..

One method in restoring Grub to the Master Boot Record (MBR) is as follows.

insert a linux live cd. In this example we will use Ubuntu 7.04 Fiesty Fawn Desktop Edition http://www.ubuntu.com/getubuntu/download

once the live cd has booted and you see the desktop.
select System --> Administration --> Gparted from the menu bar.

This should mount your linux partitions.

Close Gparted.

Open a Terminal.

Type the following commands.

sudo grub

This will get you a "grub>" prompt (i.e. the grub shell). At grub>. enter these commands

find /boot/grub/stage1

This will return a location. If you have more than one, select the installation that you want to provide the grub files.

Next, THIS IS IMPORTANT, whatever was returned for the find command use it in the next line (you are still at grub>. when you enter the next 3 commands)

root (hd?,?)

Again use the value from the find command i.e. if find returned (hd0,1) then you would enter root (hd0,1)

Next enter the command to install grub to the mbr

setup (hd0)

Finally exit the grub shell

quit

That is it. Grub will be installed to the mbr.

When you reboot, you will have the grub menu at startup.

Refrences :

http://ubuntuforums.org/showthread.php?t=224351