Partition Reorganization

[SYNass IT Ubuntu / Linux]

Hello Ubuntu System Experts
May I ask you for your advice and guidance to overcome a special
problem ?

After reorganizing my HDD with gParted it looks like following:
hda1 / ntfs (WIN XPP original installation)
hda2 / ext3 (Ubuntu installation)
hda3 / extended part (rest of HDD)
hda6 / copy of hda2 (my first Ubuntu installation)
swap at the end of the extended partition

How can I get Ubuntu starting with the one in hda6 ???

Well, in the menu.lst of both the Ubuntu partitions it shows hda2 !!

Where is the pointer to direct either WIN or Ubuntu ?
Is it MBR and how do I adjust it to my newest configuration ?

TIA for your prompt assistance and hints.
Cheers, svobi