grub reinstall for xubuntu 13.04

GRUB reinstall:
1. Boot up xubuntu 13.04 live usb stick (or dvd iso)
2. mount drive by double clicking on drive on desktop. Drive should be mounted now as /media/xubuntu/8z27xxxxblah_blah
fdisk -l (verify correct drive is mounted ie. /dev/sda)
mount    (verify correct drive is mounted ie. /dev/sda1)
grub-install --root-directory=/media/xubuntu/8z27xxxx_blah_blah /dev/sda  (/dev/sda should be same drive as /media/xubuntu/8z27xxxx)