Sometimes it is necessary to reinstall/install GRUB in dual boot systems or single boot systems.
to install GRUB:
1. Boot to the live CD/DVD/USB or rescue CD/DVD/USB (Now days, most linux distros come with GRUB).
2. Mount the partition that contains your Linux OS. as follows:
sudo mount /dev/sd2 /mnt
Note: sda2 is my Linux partition.
3. Install GRUB using the following command:
sudo grub-install – -root-directory=/mnt /dev/sda
Note: The above command is in a single line and sda is my HDD.
4. If any errors occurs, like you are unable to copy the byte and need to copy the blocks, then just type the following
command with force:
sudo grub-install – – root-directory=/mnt /dev/sda – -force
5. Reboot the system. now you can see GRUB with OS menus.
6. If yours is a dual boot windows/Linux system, then just log into the Linux paritiion, open the
terminal and type the following command:
This will add the windows OS menu to GRUB. From the next time onwards, you can see
the windows menu on booting up.