To restore grub2 run this commands:
sudo mount /dev/sda1 /mntwhere /dev/sda1 - partition for grub (with installed linux)
sudo mount --bind /dev /mnt/dev sudo mount --bind /proc /mnt/proc sudo chroot /mnt sudo grub-install /dev/sdaIf output has "chroot: cannot run command `/bin/bash': Exec format error" then your live CD architecture doesn't match with restorable.