cannot boot to openSUSE partition

my story is long but i keep it short here.
i have a 500GB hard disk and divided to 3 partitions,
1 for windows, 1 for openSUSE and 1 for Ubuntu.
i have installed and reinstalled linux on my laptop for
many many times but it is like this, Grub 2 is installed to MBR
and it workded fine but i want to add openSUSE and chose
not to boot from MBR when installing it. i had to edit the menu.lst
and got it to boot to Ubuntu partition. i also share file on partitions
directly by booting to openSUSE and take data from Ubuntu and Windows
partitions. so sometimes the pc boot i cannot scrool down the grub menu entry
and it boot directly to openSUSE. BUT it returns to the start point ( i can see Dell booting, my laptop is Dell Inspiron N5010).
and so i decided to reinstall Ubuntu(kubuntu) and set grub to install to its own partition not MBR.
Now i cannot boot to either openSUSE or Ubuntu. Only Windows is available by chance.
new problems arise now that i cannot even boot the bootable CD. Did i loose the MBR or sth?
Plz help???

From your explanation (?), I’m not quite sure what problems you are having. Can
you boot anything with this computer?

Any problems you have in booting a CD have nothing to do with your hard drive,
unless you have a hardware problem that is killing the CD drive on the same IDE
cable/controller. You will, however, need to fix that first as future steps will
require having a recovery system available.

Once you can boot a CD, please post the output of the ‘sudo /sbin/fdisk -l’
command inside code tags. Note, that is a lower-case el, not a one.

When the standard (Microsoft) MBR is installed, the code finds the active
partition and loads from it. I think that your Windows partition is active. You
need to deactivate it and make whatever partition has the GRUB loader be active.

Sorry for late reply!
I just found out that i accidently change the set up priority when the machine boot.
so now i can boot as normal.
But i dont understand cuz now change from Ubuntu 11.04 to Kubuntu 11.04 while
use grub legacy as bootloader i dont need to boot to kernel/core image or sth.
Anyway i have to boot to chainload Kubuntu through openSUSE.

thxx