There are plenty of reasons to run a virtual machine. The first, and most compelling, is that you want to play: Maybe there are some other operating system you want to dabble with (cough Linux cough), but you don’t want to deal with installing another hard drive, partitioning your existing drive, or setting up your system a different way.

Virtual machines are great because they allow you to install an operating system within your existing operating system. Everything you do within this new OS—cue Inception soundtrack—is sandboxed from your primary OS. Anything you install, or mess up, can be deleted with a few clicks of a mouse. (And if you’re smart, you saved a version of your secondary OS right after you installed it, so you can quickly go back to a clean, fresh version of Linux, Windows, or whatever.)

Even better, you can set up a virtual machine on your system for free. Here’s how to get started:

The apps you’ll need

You can pay for a virtual machine app like VMWare Workstation Pro, VMWare Fusion, or Parallels Desktop, but I recommend using the free VirtualBox app if you’re new to the wide world of virtual machines. (If you’re using Windows 10 Pro, you also get a free, built-in virtualization tool, too.)

For simplicity’s sake, all of my examples in this article will come from a Windows version of VirtualBox, but the app is cross-platform. (For Mac users, VirtualBox is a great alternative if you don’t want to Boot Camp into Windows, for example.)

A virtual machine isn’t very helpful without an operating system to install on it. And for that, you might have to get a little creative. For Windows, you can grab the Windows media installation tool and use it to download an image (.ISO) of the operating system, which you’ll then load into VirtualBox.