Ok, mount with cdrom worked, but I've given up on that part and now I'm on the Ubuntu Live disk.
Where It says, "Replace sda1 with the partiton that contains Ubuntu and sda with the drive that contains Ubuntu's partition"
sudo mount /dev/sda1 /mnt
sudo grub-install --root-directory=/mnt/ /dev/sda
What do I replace sda for? Maybe xvda?