GPT partition, no bootable disk, Grub error

There was no problem in booting from live CD/USB. Only the installation on GPT partitioned Hard Disk did not boot. We installed boot-repair tool by Yannubuntu. On blindly accepting the recommended fix it installed bootloader on all partitions as also on live USB. On rebooting the system booted Grub 2 but from USB MBR. Trying to boot from hard disk did not succeed.