[CentOS] Re-doing the MBR

I tried to install CentOS 4.4.  This was on a machine where I've got
Windows XP on the first partition (hda1).

CentOS, like most of the distros will automatically install Grub in
the MBR unless you tell it not to.  In fact it will wipe the MBR first
pretty early in the install.

Here was my problem.  During the install, the second CD had some sort
of read issue.  So I had to abort the install by intervening with the
power switch.

So when I rebooted, I couldn't boot into my XP because the MBR had
been wiped.

I pulled out an Insert distribution and did a RAM only boot up.

I could still see my NTFS partition where XP was located, and I could
also see where the CentOS installed the /boot partition in /dev/hda2.

Now I finally solved this problem by going back and doing a minimal
install of CentOS which doesn't require the second CD.

I've now got something in the MBR, and I'm up an running.  But does
anyone have suggestions on how to semi-manually install grub so that
it sees what it calls the "other" partition to boot into?  Is there a
tool out there that will do that?

I mean, what if the install had hung up on the first disk instead?
   === Al