Thank you every one for helping me. actually i followed and read every thing but just "grub install /dev/sdb" alone didn't help i also run some commands in grub as well grub install /dev/sda (not necessary ) grub install /dev/sdb grub grub> root (hd0,0) grub> setup (hd0) grub> root (hd1,0) grub> setup (hd1) grub> quit Thank Camaleón. your links literally helped me a lot. :) Thanks MYK