Red Hat 9 is rather old (released in 2003), you might have better luck with Linux using
Fedora 7 (based on RH) or
Ubuntu.
To uninstall GRUB boot loader (and restore Windows XP's boot loader) you need to use
fixboot C: and
fixmbr commands in Recovery Console.
See this how to get into recovery console, requires XP CD:
Description of the Windows XP Recovery Console.
Then, when you are in the recovery console, execute those two commands and they should remove GRUB.