#Install Grub Using Chroot
Determine your normal system partition. The following commands may be helpful. The fdisk switch is a lowercase "L".
Some helpful commands,
'sudo fdisk -l'
'sudo blkid'
'df -Th'
Mount your normal system partition. X is the drive letter.
Y is the partition number
Substitute the correct partition: sda1, sdb5, etc.
'sudo mount /dev/sdXY /mnt'
Chroot into your normal system device:
'sudo chroot /mnt'
Reinstall GRUB 2 (substitute the correct device with sda, sdb, etc. Do not specify a partition number)
'grub-install --recheck /dev/sdX'
Recreate the GRUB 2 menu file (grub.cfg)
'update-grub'
Exit chroot: CTRL-D on keyboard
Reboot is required,
'sudo reboot'