The simple way to install grub/ grub2 from any linux live-CD or any other bootable medium.

Step 1: boot from linux live CD/DVD or even USB
Step 2: mount your hdd
Step 3: chroot in the mounted filesystem
Step 3: install grub
Step 4: reboot

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fdisk -l
mount /dev/sda1 /mnt/
mount -t proc none /mnt/proc
mount -o bind /dev /mnt/dev
mount -t sysfs sys /mnt/sys
chroot /mnt/ /bin/bash
update-grub
/usr/sbin/grub-install --recheck --no-floppy /dev/sda
sync & reboot

SUSE Syntax:
update-grub is debian and ubuntu little helper this execute the same as:

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grub2-install --recheck --no-floppy /dev/sda
grub2-mkconfig -o /boot/grub2/grub.cfg
mkinitrd