Maybe when you added a new hdd you changed something that grub doesn't expect to be changed? For example, in my /boot/grub/menu.lst I have an option "splashimage = (hd0,4)/grub/splash.xpm.gz"...if it were me I'd try changing that to (hd1,4)/grub/splash.xpm.gz. You'll need a boot disk and a way to access the shell though.
If that kind of stuff don't work, do you have the original rh9 cd? I know with Fedora Core 1 it gives you the option to repair the bootloader when you pop in the cd and reboot. Mayve give that a try?