Fix grub

• Boot from live dvd (graphical desktop is ok)
• use gparted to find boot partition
• mount /dev/sdX /mnt

1. mount /dev/sda5 /mnt

• mount –-bind /dev /mnt/dev
• mount –-bind /proc /mnt/proc
• mount –-bind /sys /mnt/sys

• chroot /mnt

• grub2-mkconfig -o /boot/grub2/grub.cfg

• grub2-install /dev/sda

• chtrl-d 'exit'

• reboot