The Free and Easy Way to Downgrade from Windows Vista to XP If you have Windows Vista installed on your laptop or PC and yearn for the good old days of Windows XP compatibility and miss the familiar interface, there is a solution that will cost you nothing but your time to do it. It involves the creation of a virtual PC on your existing machine using Virtual PC 2007 software by Microsoft. A virtual PC is the just what it sounds like. A completely separate computer that runs in software on the same system as your original PC. What this means is that, you can have Windows Vista running on one virtual PC and Windows XP on the other. Both at the same time. This way, you can have the compatibility of Windows XP today and still enjoy the new software coming out that takes advantage of Windows Vista. Once installed correctly, you'll be able to switch back and forth between operating systems just as easily as you switch between programs now. The beauty of this arrangement is that it works either way. If you have XP, you can add Vista without losing your Windows XP operating system. *Note: Before making any system changes, be sure to backup your data to an external drive or other external data storage. Anytime you make major changes to your system, always take this precaution. It will save you a world of pain. Of course, free only means no money. Creating 2 virtual machines has a cost in terms of PC memory, hard drive space and performance. Installing applications in a guest OS increases requirements. Increasing memory beyond the minimum required can result in significant performance increases. A vital thing to remember before choosing a virtual machine is that you'll need lots of RAM installed on your system. More RAM than you ever thought of needing before. While you'll probably have enough CPU cycles to spare, you need enough RAM for both operating systems to run comfortably. As long as you have double your comfortable minimum, you should be fine. To really have optimal performance and take advantage of this setup, you should have at least 2GB RAM, and many gigs of hard drive space. I recommend you strongly consider a 4 GB setup if you plan on running lots of apps simultaneously and plan on using up an extra 20 gigs of drive space. Also worth noting is that installations of Windows XP or Vista will require their own product keys, regardless of whether your host computer is also running it. Since the virtual PC will see whatever hardware your virtual machine portends to have, it will assume that it is a new computer in need of new activation. You'll also need a licensed copy of Windows XP to be legitimate. Fortunately, unlike Vista, XP's EULA doesn't forbid virtual machines. Only Vista Business and Ultimate can be legally run in a virtual environment. Any other flavours of Vista could cause issues if you need official support. Microsoft has a blog for Virtual PC 2007 that you should check out before making any changes to get a better feel for what the benefits are of switching to a virtual OS and the kinds of issues you may face in running 2 OS's at once.