Re-installing Grub when MS Windows Destroyed It

Original post is here: eklausmeier.goip.de

I have now done it a couple of times, but always have to look it up. Here are the steps to re-install Grub from a live Ubuntu CD, when you have Windows and Linux on your hard disk. You must be root, or run these commands with sudo. Change /dev/sdaXY accordingly.

1. mount /dev/sda2 /mnt
2. mount /dev/sda3 /mnt/boot, if you have a separate boot partition
3. mount -o bind /dev /mnt/dev
4. mount -o bind /sys /mnt/sys
5. mount -t proc /proc /mnt/proc
6. chroot /mnt /bin/bash
7. grub-install /dev/sda

Above commands are from method 3 in GRUB (in German).