Scenario 1: Host Another Version of Windows, Under Windows Using Virtual PC 2007
If Windows XP floats your boat but you've sailed onward to Vista, an occasion might arise when you need to reverse course and return to the earlier Windows version. The ability to do so is especially handy if you're having trouble getting a favorite XP application to behave in Vista. It's also useful if you want to run even older versions of the OS, such as Windows 2000.
Microsoft's Virtual PC 2007 is the perfect fit for this virtualization scenario. According to Microsoft, the main host operating system versions supported are Windows Vista, Server, and XP Professional (32-bit and 64-bit versions), though I installed the app successfully in Windows XP Home Edition with just a brief warning that it was not supported.
When you launch Virtual PC 2007 for the first time, it displays a console listing your Virtual Machine components (which will be empty at first) and a New Virtual Machine Wizard. Click Next to start the Wizard, and click Next again, thereby choosing the default option to create a virtual machine. The wizard then asks you to confirm the amount of memory and disk space to dedicate to the virtual machine. I accepted the default memory size, but adjusted the amount of space dedicated to the virtual machine's file-based virtual hard disk downward to avoid eating up all of the free space on my host hard disk.
How much memory you devote to your virtual machine will determine how quickly it performs, but remember that any RAM you give to the virtual PC will come at the expense of its host system. If you have 2GB or more memory on your host PC, consider giving a virtual XP machine 512MB, which will ensure reasonably fast performance.
Click the final Next, then Finish, and your virtual machine will appear in the Virtual PC Console. Insert an operating system installation CD and double-click the virtual-machine icon in the Virtual PC console to start the boot process. You may need to select the CD/DVD boot drive in the Virtual PC's CD menu, choose Action, and then press Ctrl-Alt-Del to make the virtual machine boot from its installation CD or DVD. After that, the installation process should proceed just as it would on a non-virtual PC. You can install as many different virtual OSs as your hard-disk space will allow.
Virtual PC 2007 is pretty simple to use, because it has only a few options. To boot up an installed virtualized OS, select it in the Virtual PC Console and click Start. To save the current state of the OS (in order to exit Virtual PC or shut down the computer), click on Close, choose Save state from the list of options, and click OK. Clicking the mouse within the virtualized OS window once allows it to "capture," or recognize, the mouse pointer. To release the pointer for use in the host OS, press the right-hand Alt key and drag the mouse out of the Virtual PC window. Choose Action, Full Screen Mode to view the OS in a full screen, and press the right-hand Alt plus Enter to escape to the host OS.
Once your virtual machine is up and running, click Action, Install or Update Virtual Machine Additions in the Virtual PC menu. This will install a variety of tools that allow you to copy and paste text between the virtual machine and the host PC, as well as to send documents back and forth via a shared folder on the host PC.