to make a long story short, i deleted my primary partition by accident and totally jacked grub. i was able to restore it and get two of three entries back (windows, SLED 10) but i cannot seem to able to get ubuntu back. i think i killed the root file. anyways i would like to re-install but i do not want to replace the grub that i am currently using from SLED10. i dont recall from the original install if i had a choice of installing grub (i dont think i did), so that is my question; can i install ubuntu and choose NOT to install grub?

or

install ubuntu let it install grub, then reinstall grub from SLED10 and it will pick up the new addition (ubuntu). is this a correct assumption?

You can either use alternate ubuntu installation that will give you the option not to install grub OR you can backup your current grub config file and let ubuntu install the grub. Once you boot back into ubuntu, you can replace the ubuntu's grub config file with the backup grub config file. You would have to make grub entry for ubuntu to boot it.

Tux,

If you have 100 Linux distros and only one Linux to control all of them the trick is to put the Grub (or Lilo) of every other Linux inside its root partition. Thereafter you can boot any of them by "chainloading".

If you have Ubuntu in hda6 say and have installed Grub in its root partition then these lines in /boot/grub/menu.lst of Sled10 will fire it up
Grub counts from 0 as hda disk is the first disk and hda6 is known to Grub as (hd0,5).

The above is called indirect booting. It is the same technique how a Linux boots Windows. It can be done because a Window's standard installation is put its bootloader inside its own "C" drive.

In 99% of the distros you are given the alternative to install Grub (or Lilo) in the root partition, in addition to the MBR.

so just to make sure i am following, when i install ubuntu it will put grub in the root partition which is; in turn, in the same partition of ubuntu?! so this is the default of 99% linux distros?
right?

99% yes. But as tuxrules said in Ubuntu's case you will need the alternate install ISOs. If you look at their site you will find Desktop, Server and Alternate ISOs.

Edit: fixed typo

Simple distros are written to install their bootloaders only in the MBR but just about any decent Linux will allow its bootloader to place in

(a) a floppy so that it can be booted from it without the MBR assistance
(b) MBR of the first bootable disk to boot automatically from the hard disk
(c) the root partition where the Linux has been installed there, so that it can be booted by another operating system be it a Linux, a Window, Dos or BSD.

If one installs 100 distros there is only one MBR. So after the first Linux taking over it the remaining 99 distros can have their bootloaders installed in the respective root partitions and everyone can be booted by chainloading by the first one. This is standard technique and definitely the quickest and easiest. More importantly chainloading works for Lilo too by its "other=" statement and so all the Linux can be mixed and booted together by one boot loader. Lilo has a fixed screen restricting its ability to displace no more than 27 entries for booting. Grub has a scrolling screen and so over 100 distros can be accommodated.

The other method is to boot the 99 distros directly by naming the kernel and initrd files locations in the /boot/grub/menu.lst for Grub or /etc/lilo.conf for Lilo that controlling the MBR.

Within each distro you can tell Grub to place itself in floppy, MBR or root partition (Say hda7) respectively any time you please by commands
Same for Lilo with commands
Putting the bootloader at a location is a freedom any user can choose to suit his/her need. There should never be a need to destroy any boot loader once it is installed.