repair grub linuxmint 16

sudo mount /dev/sdXY /mnt
sudo mount --bind /dev /mnt/dev && sudo mount --bind /dev/pts /mnt/dev/pts && sudo mount --bind /proc /mnt/proc && sudo mount --bind /sys /mnt/sys
sudo chroot /mnt

grub-install /dev/sdX
grub-install --recheck /dev/sdX
update-grub

exit && sudo umount /mnt/dev && sudo umount /mnt/dev/pts && sudo umount /mnt/proc && sudo umount /mnt/sys && sudo umount /mnt