> **Possible Duplicate:**  
> [Is Windows 7 Windows XP mode the same as running a Virtual PC with XP on it?](http://superuser.com/questions/64420/is-windows-7-windows-xp-mode-the-same-as-running-a-virtual-pc-with-xp-on-it)  


Windows 7 Ultimate has a Windows XP Mode, and it is **not** supported for Windows 7 Home Premium version.

The question is, why do I need it?  Can't I just download Microsoft Virtual PC and the XP disk image and be able to run XP?  Maybe the catch is that it will expire.  Is that the only difference?