As explained by the HowToGeek people,
“Virtual machines allow you to run any operating system in a window on your desktop. You can install the free VirtualBox or VMware Workstation (both of them free), download a Linux distribution such as CentOS or Ubuntu, and install that Linux distribution inside the virtual machine like you would install it on a standard computer.
When you need to boot up your Linux system, you can do it in a window on your desktop — no need for rebooting and leaving all your Windows programs behind. Everything but demanding games and advanced 3D effects should work just fine.
Here are two interesting YouTube videos:
Installing Centos7 in Oracle VM VirtualBox
Installing CentOS 7 in VMWare Workstation 10