I boot from the installation DVD, with an already existing CentOS 5.5 system on my hard disks. I have separate boot, root, and home partitions. I have moved the boot partition and now I need to re-initialize grub from rescue mode. Attempting to use 'rescue mode" to automatically mount my system under /mnt/sysimage eventally fails with an error message, which essentially says 'mount error' and nothing else. I am then put at a command prompt as root. So now I decide to manually mount my partitions at /mnt/sysimage and then do a chroot to /mnt/sysimage. This succeeds and when I look at my files they are there. I now try 'grub' and the 'grub' shell comes up. I now attempt the 'grub' command: root (hd0,9) only to be met with: Error 21: Selected disk does not exist. I do not know what this means and how I can correct it. Does anybody know what is going on ? One thing I am concerned about is that when I booted from the DVD and was eventually put at the command prompt, I saw there were devices in the /dev subdirectory but after I did the chroot, there were no devices in the new root's /dev subdirectory although when I had previosuly booted into CentOS 5.5 on my hard disk off course they were there. The other thing I noticed is that after the 'chroot' the 'mount' command showed only my root partition mounted on /dev/sdb8 where it actually exists ( along with sysfs and proc which I mounted from the old root ). But despite this there are no subdirectories under the new root's /dev. I am just trying to re-initialize 'grub' so I can boot my CentOS 5.5 system again. There must be a way to successfully do this from the installation DVD. If somebody can give me the steps to manually mount my partitions and succeed it would be very much appreciated.