You must download Virtual PC for Windows 7 from the following location rather than the Microsoft Virtual PC website: Microsoft provide a useful HAV detection tool which can help you with BIOS configuration. The BIOS menu is normally accessed by pressing DEL, F2, or ESC immediately after switching on your PC. This is supported by most modern processors, but it may need to be enabled in your BIOS. XP Mode requires hardware-assisted virtualization (HAV).
However, there is a workaround that allows Windows 7 Home developers to use XP Mode integration. This is unfortunate since the vast majority of new PCs have those editions installed. Windows 7 Home Basic and Premium users are unable to use XP Mode. Unfortunately, it only worked on the Professional, Ultimate or Enterprise versions of Windows 7. My recent article, Run IE6, IE7, and IE8 on the Same Machine Using Windows 7 XP Mode, provided instructions for installing Virtual PC and XP Mode on a Windows 7 PC.
