If I was doing what you wish, I would only handle this by switching between drives at BIOS level and keeping Win 7 and XP totally independent. One other thing you might consider is to make sure your Win 7 is not an upgrade from the XP installation on the other drive using it to qualify for that upgrade.
Can anyone assist me in putting together a dual boot using Windows 7 on a Sata drive and using Windows XP on a IDE drive.
Dryzone had a method to do some editing on the boot.ini files in XP and Vista. I started to do this process, but I was not sure where to copy the boot.ini from XP. Also Windows 7 does not have a boot.ini now but instead it is called bcdboot. In order to edit this file you use a application called Bcdedit on the command line, but again where is this command line in Windows 7.
So has anyone setup a dual boot system using Windows7 / Windows XP? Any answer but above would be greatly apprecated.