This HOW-TO specifically details how to create a dual boot system using Redhat Linux 7.2 and Windows XP with a NTFS file system using the GRUB boot loader.

The Problem: The problem was stumbled upon after I successfully persuaded my Windows XP-using-friend to install Redhat Linux 7.2 onto the empty end of his hard drive. "Sure." I tell him, "dual booting will be no problem!" A few days later he calls me up frustrated saying that he can no longer access his Windows XP operating system....

The procedure I gave to my friend for the install was one that I had learned from past experience. Knowing how MS Windows XP likes to overwrite the MBR(Master Boot Record), I tell him to:

fdisk the Hard drive and make a partition for Windows XP and leave whatever you want to allocate to Linux unpartitioned.
Install Windows XP onto this partition. (This should be a primary partition!)
Boot to the Linux install CD and partition the remaining unpartitioned part of the HD and install linux. (Install GRUB into the MBR, it should detect both OSes)
Reboot and enjoy your new dual boot system!
Redhat 7.2 uses the new GRUB bootloader. During the Redhat install, Grub actually *WILL* detect your NTFS XP partition. However, if you do not give this partition a label at that time, then booting to your Windows XP OS will not be an option under GRUB. It is apparent that many (and I mean thousands!) have overlooked this step during the install process, and hence the need for this article. If booting to Windows XP is not an option for you at boot, then you have missed this step and the lines below will solve your problem by manually editing a configuration file and labeling the partition so that it is selectable at boot.
My friend missed this step as well and panicked when he couldn't get to Windows. His first instinct of course was to reinstall Windows. A typical microsoft approach, but "No" I tell him, "The XP operating system is still on your harddrive, GRUB simply cannot see it." Having very little experience with GRUB, since previous releases use LILO, I was unsure how to fix the problem. I had a good guess it was probably just a simple mod to the /etc/grub.conf similar to how LILO operated. Indeed this is the answer! I scoured the net for quite a long time looking for the few lines of code that would enlighten GRUB to the existence of XP. I found that many others had dealt with the exact same problem. Unfortunately, a proper answer was more than I could hope for! So here is the solution for all to see who might try this very common procedure. Add the following lines to the /etc/grub.conf file:

title Windows XP

root (hd0,0)

makeactive

chainloader +1

As it says in the grub.conf file. You do not have to restart GRUB as you did LILO for the changes to take affect. Simply save the file and reboot. All should be well. If you find yourself in a similar circumstance but you are using LILO instead, these lines can be added to the /etc/lilo.conf to fix the problem:
other=/dev/hda1 (device XP is installed on)

label=Windows XP

table=/dev/hda

Restart LILO (I believe you can just type lilo at the prompt to do this) and then reboot. I hope this short HOW-TO of my experience with dual booting XP and Linux on the same HD has helped you. My apologies if your system has further issues that this document does not solve. I am no Linux expert, just a hobbyist trying to document my findings.