NComputing

The NComputing solution separates a desktop PC environment from a physical machine to create a client-server computing model. That is, a user's desktop is hosted remotely and accessed via a access device over the network. A user no longer has a physical PC.
Windows XP instead of Windows Server software
Only under very limited circumstances. If you (the customer) have licensed the appropriate number of Windows Server operating system and associated Client Access Licenses for simultaneous access by multiple users to the Licensed Computer, you may install and run the NComputing vSpace Software on a separately licensed Windows XP Client operating system in lieu of the Windows Server operating system. You may only install and use either the Windows Server operating system software or the Windows XP Client operating system software but not both. Note that while Microsoft allows this limited use of the Windows XP client operating system configuration under these specific circumstances, support for NComputing’s vSpace software running on Windows XP is solely provided by NComputing. Microsoft does not provide any support for NComputing vSpace Software or for the Windows XP Client operating system in this configuration; you should seek support from NComputing for issues relating to the NComputing vSpace Software and its use with the Windows XP Client operating system.source:http://www.ncomputing.com/