Restoring Grub Boot Loader Ubuntu

Boot using the Ubuntu Desktop LiveCD

- Open a terminal (Applications -> Accecoriess -> Terminal)

- Identification of ubuntu already installed on your computer, by typing the command:

code
$ Sudo fdisk-l

- Perform mounting the partition with the command:
$ Sudo mount / dev/sda5 / mnt

- Then install grub that has a mounted partition with the command:
$ Sudo grub-install - root-directory = / mnt / / dev / sda

if successful it will exit the message; install completed with no errors.

- Reboot your computer, Grub loader should have appeared

may be useful