If you have never heard of virtualization, then I highly recommend that you get yourself familiarize with it, at least conceptually. Basically with virtualization, you can run different copies of the same version of Windows or different versions of Windows on the same physical machines. These "guest" Windows are isolated from each other to some extend. This enables a lot of possibilities. Actually, you can run guest operating systems that are not Windows. You can run Linux and other exotic systems on the same physical machine. Think about this, you only have to buy one physical machine to run half a dozen copies of Windows simultaneously. It's like having multiple physical computers in your room.
Needless to say, because the computer runs multiple copies of Windows at the same time, this computer needs to have a bit of beefy CPU, lots a memory, and last but not least the type of virtualization technologies that the CPU supports.
Assuming that the host physical PC has an Intel CPU. At the very least, this CPU has to support VT-x. There are a few other members of the VT family. They are VT-x, VT-i, VT-d, and VT-c. Below is a brief introduction of what these are and what they can do for you in terms of your using virtualization.
https://www.thomas-krenn.com/en/wiki/Overview_of_the_Intel_VT_Virtualization_Features
