Remove Grub and then re-install.

Remove:
Code:
sudo dpkg --purge grub-pc
sudo apt-get remove --purge grub-pc
sudo apt-get clean
sudo apt-get autoremove
sudo apt-get update 
sudo grub-install /dev/sdX
[## where 'X' is the HDD Number like /dev/sda or /dev/sdb]
sudo update-grub