Virtualization is built into Windows 8

Whereas in Windows 7 and previous versions of Windows there were Virtual PC and Windows XP mode (a great feature that will persuade many a skeptic about upgrading from Windows XP to Windows 7) there is now Hyper-V, the incredible and mature Microsoft virtualization system. Hyper-V, now up to par with the leader VMware, is built into Windows 8 (though the Desktop version) but still useful to install and control a number of virtual machines using the Hyper-V Manager. The first step to take is to enable it by accessing "Turn Windows features on or off" (to do that, while in the Start screen, the one with the tiles, type "features" and then select "Settings") to reveal the application shown here. There is plenty to learn here and it's the wave of the future. The link to MSDN, up there, includes a great video explaining how to enable and install Hyper-V, including the trickiest part: networking and Internet access.