Lost your grub after windows installation.. How to update, reinstall the grub in (BOSS) Linux?

Scenario:
  Once windows(vista, 7, xp) installed after the linux installation then one will lost his grub and there is no way to select the OS during the system startup(Dual Boot).  By default windows installs its boot loader into the MBR and not care about the other OS in the same machine.
So how to get the old grub with the new Windows OS entry in it..? here follows the steps..

1. Insert your BOSS Linux DVD(live, install, utility all are in the same DVD) in the drive and reboot your
system.
2. Select the live option and boot your system in live mode.
3. Click and mount the Linux partition whose grub is going to be used.
4. Now copy the mount location in the addressbar(location: it is somewhat like /media/some_chars_numbers)
5. Open your "root terminal" Applications --@ Accessories --@ Root terminal and issue the following commands
6. #mount --bind /dev /media/some_chars_numbers/dev
7. #chroot /media/some_chars_numbers
8. #update-grub
This updates the grub with the newly installed Windows OS entry in it
9. #grub-install /dev/sda
This installs the grub in the MBR(Master Boot Record).

Thats all.. now reboot the system and remove the DVD.  Now system will loads with the new updated grub where you can see all the OS available in your system and you can select(dual/multi boot) the OS which you want to login.  That's all :)