Windows Virtual PC is a virtualization module available for Windows 7 and enable users to install different versions of Windows on the same computer.
The program can be installed only on a few versions of Windows and, as guests, supports only a limited number of versions (Windows 7 and prior).
You can choose a custom amount of RAM memory and HDD space for each guest. Also, you can activate the Undo Disk option to backup each virtual machine in different moments.
You can install only a few versions of Windows, it doesn't support Linux, Mac OS or others.
You can share folders between host and guests, but doesn't support drag & drop. Also, you cannot customize the number of processors allocated for each guest.
The program provides a detailed help manual (F1) and there is available an online forum for support.
The program is not very easy to use the first time, but once you will setup the first virtual machine, you will discover useful options and features to customize it. It can be a good solution if you don't like Oracle's Free VirtualBox.