Reinstalling GRUB bootloader

[mylar]

Hi folks... My dad has a dual boot computer in his home office currently
booting Windows XP and Fedora Core 3. Windows XP resides on an 80 GB
SATA drive and Fedora resides on a 200 GB IDE drive. The boot sector is
on the SATA drive. Recently  the SATA drive crapped out and the machine
will no longer boots XP. GRUB still comes up fine however and the
machine still boots into Linux just fine. Now, here comes the kicker...

Since  it's a Dell machine and is under warranty Dell is sending me a
new replacement SATA drive. Problems is, once I install it and
re-install XP on it I know I am no longer going to see GRUB on startup
and the machine is going to boot into Windblows only. 

So here's the question. How do I reinstall GRUB ?? In the old days with
LILO it was easy, just boot Linux off a  floppy and run "$ lilo". But
nowadays the kernel images are too big to fit on a floppy. So what are
my options ??

Can I make a boot CD Rom or DVD and boot in from there and reinstall
GRUB ?? Can I used the fedora Core 3 distro discs ?? Can I use a Linux
distro on CD (such as Knoppix) and fix it from there ?? if so, what do I
do ?? How do I get my  boot info back where it belongs ?? Do I have to
re-install Fedora from scratch ?? 

In other words HELP !! What do I do ?? How do I make the machine dual
boot again ?? How do I get GRUB back ??  

mylar