A. Windows 7 is still available as a 32-bit OS, so if you have an XP based desktop with a virtualization platform such as Virtual PC installed, it is possible to install Windows 7 in a Virtual PC environment. However, none of the enhanced desktop composition features such as Aero Glass would be available, because XP doesn't support desktop composition. Also, the VM's performance would be limited to the features supported by XP and the virtual platform. You certainly won't get a full Windows 7 experience.

The more common configuration would be to install Windows 7 on the desktop and run XP in a Windows Virtual PC VM, so that XP could run applications that aren't supported on Windows 7. This configuration gives the added bonus of seamless application windows, which means the application window from the VM is displayed seamlessly on the Windows 7 desktop without a separate Start bar, notification tray, and so on.

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