Authored by Dave Mallisk in Computer Software 
Published on 11-03-2009

Windows 7 virtualization includes running Windows 7 as either a host OS (Operating System) or a guest OS (virtual OS). When you run Windows 7 as the host OS, you can run another operating system, such as Windows XP or Linux, within it as its guest OS. When you run another OS, such as Mac OS X Snow Leopard, as the host OS, you can run Windows 7 within it as its guest OS. For more general virtualization information, see the Benefits of Virtualization article.

Windows 7 as Host OS

To run Windows 7 as the host OS, you can use either of the following:

• Windows XP Mode
• Third-party virtualization software

Windows XP Mode for Guest OS – Windows XP Mode (officially called Windows XP Mode and Windows Virtual PC) is a virtual XP SP3 Professional OS that is included in the purchase price for Windows 7 (Professional or Ultimate). The preinstalled Windows-Virtual-PC component lets you download and install the Windows-XP-Mode component that lets you run Windows 7 as the host OS and Windows XP Mode as its guest OS.

If you are currently planning to upgrade from XP to Windows 7 Home by either buying a new PC with Windows 7 Home already installed, or upgrading your PC to Windows 7 Home, you should first ask yourself whether you are content with all your applications that currently run under Windows XP. If you are content with all or most of these applications, you should consider instead upgrading to Windows 7 Professional so that you can download and install Windows XP Mode. In most cases, the extra cost for Windows 7 Professional should be much less than the total you would need to pay to replace multiple applications for XP with comparable applications for Windows 7.

Most, but not all, new PCs contain virtualization-capable hardware. Windows XP Mode requires hardware-assisted virtualization. Therefore, most new PCs can run Windows XP Mode as a guest OS within a Windows 7 host OS. To determine whether your PC contains virtualization-capable hardware, you need to run Microsoft’s Hardware-Assisted Virtualization Detection Tool (and, if necessary, enable hardware-assisted virtualization) as explained in Microsoft’s Configure BIOS web page.

To download, install, and run Windows XP Mode, do the following:

1. Install the latest updates to Windows 7.
2. Download and install Windows XP Mode according to the instructions on the Download Windows XP Mode web page.
3. While running Windows XP Mode:
   1. Install the latest updates to Windows XP.
   2. Install your applications for XP.

Third-Party Virtualization Software for Guest OS – Third-party virtualization software lets you run almost any OS (such XP, Mac OS X, or Linux) as the guest OS within your Windows 7 host OS.

Third-party virtualization software available for your Windows 7 host OS includes:

• VirtualBox for Windows Hosts, which you can download from the VirtualBox Downloads website. For example, here is a procedure for using VirualBox to run Ubuntu (a Linux distribution) as a guest OS within a Windows 7 host OS: Windows 7 and VirtualBox Compatibility Testing.
• Parallels Desktop 4 for Windows and Linux, which you can purchase and download from its Parallels website.

Windows 7 as Guest OS

You can run Windows 7 as a guest OS. Two examples: You can run Windows 7 as a guest OS within either of the following:

• Mac OS X host OS
• Linux host OS

Mac OS X as Host OS – To run Windows 7 as the guest OS within a Mac OS X host OS, you can use the following third-party software:

• VirtualBox for OS X Hosts, which you can download from the VirtualBox Downloads website.
• Parallels Desktop 4.0 for Mac, which you can purchase and download from the Parallels for Mac website.
• VMware Fusion, which you can purchase and download from the VMware website.

Linux as Host OS – To run Windows 7 as the guest OS within a Linux host OS, you can use the following third-party software:

• VirtualBox for Linux Hosts, which you can download from the VirtualBox Downloads website.
• Parallels Desktop 4 for Windows and Linux, which you can purchase and download from the Parallels for Linux website.