I think we have a problem here in that you either may not know where you have stored the various parts of your RHEL or the Linux installation was incomplete if you do not have a menu.lst. This is the file Grub uses to execute the booting. Grub needs it in order to know

(1) Which is the root partition to be booted?
(2) Which kernel to be booted?
(3) Is there a ramdisk file to be loaded?
(4) What are the other booting alternatives

May I suggest you to replicate the bootloader in a floppy, possibly using the RHEL recue disk or from a fresh installation. Have the RHEL in a working order and copy the first 512 bytes of the floppy to your favourite Windows booting directory for NTLDR to boot the Linux.

I know you have apprehension of letting Grub to take over the MBR but it is the only boot loader that can boot any number of DOS, Winodws and XP you throw at it. You need no fear of losing Windows MBR because it can be replicated any time, using Windows installation CD (by fixmbr command) or just a bootable DOS floppy (by fdisk /mbr command).

In you case your RHEL could have been booted up manually using a Grub bootable floppy "unattched" to any operating system, if the system is bootable originally.

You may think it is safer to stick with NTLDR as it is already dual booting your Win98 and Win2k but it is in fact simpler using Grub.

In my box Grub is booting 50+ systems including RH, Win98 and Win2k. Grub is simple because it can boot all systems with the same 3 lines of commands without knowing what kind of system it is. The standard 3 lines are

label this is the operating system in disk i partition j
root (hdi,j)
chainloader +1

If you have 10 systems just repeat the above 3 lines 10 times in your menu.lst. The necessary condition for Grub to chainload any system is a boot loader must be installed in its root partition. You have done this already with RHEL. Windows, DOS, BSD and Solaris systems also do this automatically
so no extra work is needed.

This is what I mean by Grub can boot 10 times more systems with only 1/10 of the effort (of NTLDR).