XP Mode is a fully-licensed copy of XP, the license for which is included with your Windows 7 Professional, Enterprise, or Ultimate version, which are the only versions XP Mode will work on.  You can use your own legit copy of an OS to install, but even it  you use a legit XP disk/key to install, it will not be an instance of "XP Mode" but simply a VM running XP in Windows Virtual PC.  You can install any 32-bit OS as a VM in Virtual PC.  XP Mode is essentially a pre-configured VM running XP.  Whether installing XP in a separate VM or as XP Mode, you will be limited to a single instance by virtue of your XP license.
        My recently delivered XPS 435t/9000 came with no instructions or information on partitioning the 1 TB hard drive, nor anywhere else on the dell.ca and dell.com websites can I find such information.  Surely they don't expect advanced users to be content with a single 1 TB partition and one drive letter, or is it the case as I've heard that the computer comes with an empty D: partition (I' m still planning what to do on the first boot, so I haven't looked)?  Other than the Recovery partition, etc I'd like to configure the drive into 4 partitions (C: to F:, of roughly equal sizes)         I presume WIN 7 PRO x64 supports multiple partitions on at least the primary HD, but can find no Dell documentation.  I believe that WIN 7 itself  has a built-in partitioning utility in Disk Management,  or else I have a copy of PartitionWizard 5 which says it supports WIN 7 x64.          A somewhat related question, please: I will be installing Virtual PC/XP Mode shortly, which I presume automatically/no option uses partition C: - should I do that before I partition the drive, or is afterward also OK (I plan on allowing 250 GB for drive C:)? Does the size allotted to the C: partition affect the performance of a virtual PC or the XP mode? Thanks for your help.....
Partitioning Issue in WIN 7 Pro x64