So youre saying not to bother with dual boot and that if xp is installed on a seperate hdd, witout the Windows 7 hdd on the computer, that i just need to set boot priority to the xp hdd to boot xp and set to Windows 7 to boot in Windows 7?
Absolutely - that is the best way of doing it provided you unplug the Windows 7 HDD during the XP installation. Both systems won't 'know' each other.
For cleaning up a dual boot configuration, I have written this tutorial
- just in case you run into this situation again. If you do it right, it is not a big deal.