Manually installing GRUB

From Granular Linux Documentation

Introduction

You usually need to manually install GRUB (GRrand Unified Bootloader) when either your GRUB is giving some error or when Windows installation has overwritten the MBR.

What to do?

Whenever Windows XP is installed on the hard disk which contains Granular (or Linux in particular) already installed, Windows XP installer overwrites the Master Boot Record (MBR) settings. That means the MBR, which previously pointed towards GRUB (the bootloader for Granular and most Linux distros), now points towards NTLDR (the bootloader for Windows XP). As Windows does not recognize Linux partition, you don't get the option of booting into Linux.

In such a case, you can re-install GRUB such that the MBR is reconfigured to point towards GRUB. Linux can recognize all the partitions of Windows and that's the reason GRUB gives you the option of booting into Windows as well.

To re-install GRUB, boot normally from Granular LiveCD (or from any live cd that has GRUB installed). Then open the terminal (Konsole) and execute the following commands: (Assuming that Granular is installed on the x+1 partition of your first hard disk)

# grub
grub> root (hd0,x)
grub> setup (hd0)
grub> quit