If you are dual booting Windows and any popular flavour of Linux, chances are that you will encounter the dreaded - Grub 22 error, sooner or later, It happens when the Master Boot Record gets wiped off. One reason could be , GRUB (Grand Unified Boot Loader) was installed on a windows partition, and you re-installed Windows, aha! Windows will place its boot loader and happily wipe off GRUB. Panic not! All is well with Operating Systems (Windows/Linux), what we need to revive is a small launchpad for loading the Operating System. So, how do we revive GRUB ?

1) Pop in your Live CD (Say Ubuntu Linux) and boot.
2) Open a terminal and type

sudo grub

3) You will be greeted with the grub> prompt, Now type

find /boot/grub/menu.lst

4) Assuming you get an output (hd0,5), it means that the MBR was on harddisk 1 (hd0) and on the 6th partition , say /dev/sda6 . Now type the following

root (hd0,5)
setup (hd0)
quit

5) Reboot and get back your Revived GRUB!


Footnote:
1) May I recommend Installing GRUB on a Linux partition, and setting it as the bootable partition (use fdisk), so that Windows does not wipe out GRUB.