To fix GRUB 2, you need an Ubuntu live CD from which you need to boot. Once you boot to the LIVE CD, open a terminal an and type these commands:
Firstly, you need to find out on which partition your Linux system is installed:
sudo fdisk -l
Now, we must mount this partition:
sudo mount /dev/sda1 /mnt
Where “sda1” is the partition where you installed Ubuntu (or any other Linux distro). It could be “sda5”, “sda6”, etc. for you.
Install grub to the partition you’ve mounted:
sudo grub-install --root-directory=/mnt/ /dev/sda
Important: Please notice that it’s “/dev/sda”, not “/dev/sda1”. “sda” is the hard disk on which your Linux distribution is installed!
Restart your computer. As previous Grub 2 entries are removed, run the following command to restore them:
sudo update-grub
