Boot up ubuntu from the livecd,open terminal and run:
sudo -i mount /dev/sda7 /mnt mount /dev/sda6 /mnt/boot #skip this one if not have a separate /boot partition grub-install --root-directory=/mnt/ /dev/sda
If you miss “grub.cfg” file,use following to recreate:
mount --bind /proc /mnt/proc mount --bind /dev /mnt/dev mount --bind /sys /mnt/sys chroot /mnt update-grub umount /mnt/sys umount /mnt/dev umount /mnt/proc exit
