Lets you run DOS, Windows, and even Linux operating systems on one PC without partitioning; shares files between virtual machines. Key features
Microsoft has added several new features to Windows Virtual PC to make it easy-to-use and to help you run many older Windows XP applications in Windows 7.
* Easy setup of Window XP Mode
* One click launch of Windows XP Mode applications
* USB support

Check out just a few of Windows Virtual PC's newest features:
Easy setup of Windows XP Mode
Once both the Windows Virtual PC and the virtual Windows XP environment are installed, Windows Virtual PC provides a simple wizard to set up Windows XP Mode with just a few clicks.
USB support
Users can access USB devices attached to the host directly from virtual Windows XP. These devices include printers and scanners, flash memory/sticks and external hard disks, digital cameras, and more.
Seamless applications
Publish and launch applications installed on virtual Windows XP directly from the Windows 7 desktop, as if they were installed on the Windows 7 host itself.
Seamless applications
Publish and launch applications installed on virtual Windows XP directly from the Windows 7 desktop, as if they were installed on the Windows 7 host itself.
Clipboard sharing
Cut and paste between your Windows 7 host and any virtual machine.
Printer redirection
Print directly to your attached printer from your seamless software or virtual machine.

* Integration with Windows XP Mode
Users can run many Windows XP productivity applications in Windows XP Mode, which is available for Windows 7 Professional, Windows 7 Ultimate, and Windows 7 Enterprise. Windows Virtual PC provides the integrated install experience for Windows XP Mode that is simple and easy-to-use.
* USB support
Windows Virtual PC supports many USB devices such as printers, scanners, flash memory/sticks and external hard disks, digital cameras, and smart card readers.
* Seamless software publishing and launching
Users can launch and use their line of business applications installed in the Windows XP Mode directly from a Windows 7 desktop, as if these are Windows 7 capable applications.
* Support for multi threads
Users will be able to run multiple virtual machines concurrently, each running in its own thread, which improves stability and performance.
* Clipboard sharing
Cut and paste between your Windows 7 host and any virtual machine.
* Printer redirection
Ability to redirect printing from guest machine to printers attached on host machine. With integration features enabled, the drivers need to be present on the host as well as the guest. However, Basic Mode would not require host side drivers to be present necessarily.
* Smart card redirection
Ability to support smart cards connected to the host, inside the guest operating system. Smart card redirection works in a similar way to printer redirection. It is not available with integration features enabled.
* Drive sharing
Drive sharing is a more flexible sharing option. This includes sharing any mass storage devices. Virtual PC 2007 allowed folder sharing.
* Integration with Windows Explorer
Windows Virtual PC console is integrated with Windows Explorer so that users can manage all of their virtual machines from an easily discoverable folder (%User%\Virtual Machines).
* Known folder integration between host and guest
Users can access their Windows 7 Known Folders (such as My Documents, Pictures, Desktop, Music, Video) from within a virtualization Windows environment such as Windows XP Mode.
* Support for higher resolutions
The allowable resolution for virtual machines has been extended up to 2048x1920 from 1600x1200.

The license of this software is Freeware, you can free download and free use this system utility software.