If you were moving system from one machine to another (e.g. physical to virtual machine) and you stuck on installing grub to mbr:

root (hd0,0)
setup (hd0)
 Checking if "/boot/grub/stage1" exists... no
 Checking if "/grub/stage1" exists... no

then I have a solution for you. If you checked dozens of pages (like I did) that say there`s a problem with your grub files and you checked them hundred times that everything is fine (files were there, you can still install grub on the source system using exactly the same set of files) then do not loose hope You might want to check if your grub is able to read your filesystem. Maybe you created fs using newer tools. I was moving Fedora Core 3 using sysrescuecd. I created partition and filesystem using tools available on that system. It seems that probably there were minor changes between ext3 fs created on FC3 and sysrecurecd and therefore after chrooting to FC3 environment I couldn`t install grub.

The solution is quite simple – do it outside chroot environment!

Once you have mounted your root partition with /boot install mbr using grub from your livecd environment. In my case I had it mounted on /mnt/custom so I had to enter the following command to install grub on /dev/sda:

grub-install --root-directory=/mnt/custom /dev/sda

I didn`t find a way to do this using grub command line, but using grub-install I was able to boot my system and that was what I needed.