Yeah, all you have to do is get a copy of Gparted, which is completely free (downloadable from
this link), and use it to hide the first XP's partition so the install program wont see it when you install the second XP. You should probably also set the "active" flag to the new XP's partition first, before the install, too. And then, once the install of the second XP is finished, simply plug the other HDD again, so Win 7 is in control, and then use
EasyBCD 2.0 Beta to add an XP entry to the Win 7 boot menu (or, on second thought, since there will probably already be one, since you have an XP installed, just delete the current one and create a new one). Doing this will run EasyBCD's auto-configurator for boot.ini which will add the second entry to your boot.ini file, to boot the second XP. And then your boot menu will look something like this:
Win 7
Win XP
and when you select the Win XP entry, and press Enter, you will see another menu with two XP entries. Select the first to boot into the first XP, or select the second to boot into the second XP.
Good luck.
