To be honest, I have had many issues with partitioning in the past, some of which so bad that I now steer people away from that route. I personally would recommend instead to install Windows XP on a virtual machine using VMWare (
http://www.vmware.com/products/player/overview.html). It would allow you to run Windows XP on top of Windows 7.. Or any other operating system that runs on x86 architecture. Of course, you'd need a powerful enough machine to do so. If it was built within the last year or two, and has more than one core and at least 4 gigs of ram, it should be fine.