GRUB to boot other disks

[Hadders]

Hi all,
  I'm just wondering if I can use Grub to boot another disk.

I've got my primary boot drive as a RAID container. After install I've 
plugged back in /dev/hda and /dev/hdb (paranoid in case something went 
wrong) and now I'd like to have Grub which was installed onto the MBR of 
the container boot /dev/hda partition (0), which is Windows XP.

I thought I could just go
rootnoverify(hd1,0)
chainloader +1

And it would work, but it didn't?  Do I need to reinstall Grub now that 
I've plug devices back in? Would it need to create a new device map or 
something?
What are those commands? (sorry, being lazy).

Thanks. Hadders