How to Fix Grub Error in Ubuntu Linux

Boot with Ubuntu live cd , open a terminal and run: :~$ sudo fdisk -l :~$ sudo su :~$ cd / mount /dev/sda12 /mnt #(Here my Root system is in sda12 shown from the 1st command) # next line only if you have a separate boot partition :~$ mount –bind /path/to/boot-partition /mnt/boot  # if no separate boot partition, please continue: :~$ mount --bind /proc /mnt/proc :~$ mount --bind /sys /mnt/sys :~$ mount --bind /dev /mnt/dev :~$ chroot /mnt # in the chroot session: :~$ update-grub # if update-grub fails :~$ grub-install /dev/sda # if you get any errors  please use this command : :~$ grub-install --recheck /dev/sda # now you can exit the chroot, unmount the system and reboot your box : :~$ exit :~$ sudo umount /mnt/dev :~$ sudo umount /mnt/proc :~$ sudo umount /mnt :~$ sudo reboot Enjoy...