Short answer, what I do in this instance; fire up GParted from the liveDVD(USB) - the install media for a desktop - and ->
delete the partitions I no longer want ( old operating systems) .. that yields " unallocated space" . In GParted I set up the new partition(s) - /, /home and swap as the basic minimum for my use case .
In the installer I choose the option "something else" and direct the installer where I want what installed to which partition.
In the final install stage grub will be installed. Pay attention and direct the installer where to install the boot loader ( grub) to.
Reboot into ubuntu when the install complets. and run terminal command:
to insure that grub picked up and chainloaded the Windows (XP) install onto it's boot menu.
caveat : The 7 Ps
Prior Prudent Planning Prevents Pi** Poor Performance