Your underlying problem is that Linux distros are not particularly designed to "play well" w/ each other. Upon installation, each one thinks it is supposed to be in control & presumes that the MBR is its to take over. Sometimes the new boot menu will have a few entries for the previously installed OS's, but then the result is cluttered and usually not complete. You then have to go in and once more edit a bootloader configuration file to get things right. After about the 2nd or 3rd time, this get old. Here is how I avoid the problem ...
When I set up a multi boot system of *nix OS's, I use a separate "Master" bootloader that chains to everybody elses' bootloaders. This is a bit of a pain to set up, but it beats the alternative. So far, I have only used GRUB as this Master Bootloader, but I have a friend who loves GAG & keeps urging me to try it out. Using GRUB as the master requires that it (the master GRUB) either share a partition w/ one of the installed OS's, or have a (very small) dedicated one of its own.
GRUB can be the "Master Bootloader" because it can chain to lilo or another instance of itself as easily as to a Win install. The Master Bootloader is installed to the MBR and each OS is told to install its bootloader to its root partition. (I don't bother w/ separate boot partitions in this situation -- too much partition clutter.)
The advantages are:
* You never have to modify any OS's menu.lst (grub.conf) or lilo.conf.
* You see exactly what the distro intended you to see.
* Your boot menus are uncluttered.
* When you add an OS, you change a file that you understand, because you
* Said change is the addition of a simple 3 line chainload section.
The disadvantages are:
* You have to learn (RTFM^2) grub-install.
* You have to protect your MBR during OS install.
* You have to back up your MBR.
"Tux" is semipublic machine for new & prospective GNU/Linux users to test drive a variety of distros and compare them against each other & even Win93SE.
Its partition layout looks something like this:
MBR GRUB binary ("master") => hda1
hda1 GRUB partition
hda2 Win98 SE
hda3 Linux swap, shared
MBR FreeBSD boot binary
hdb1 FreeBSD install
hdb5 /Data (common to all)
hdb6 Debian Sarge
hdb7 SimplyMEPIS 2004.06
hdb9 Mandrake 10
hdb10 SuSE 9
hdb3 RH server (Samba study group)
hdb4 SuSE server (Samba study group)
Here are some excerpts (from memory) from the corresponding /hda1/boot/grub/menu.lst
# This is the master boot menu
# Do NOT let it be overwritten during OS install
# Put only chaining sections in this file
colors light-red/red white/red
title Samba Sub-menu
Note the ability unclutter by using sub menus.
Note that (hd1) means the MBR of hdb.
Hope this isn't too long or too unclear, and someone finds it useful.