If you need to run more than one operating system on your Windows 10 PC there are several ways to do it. You can have separate hard drives for each OS, and connect only the one you need before you press the power button. Or, you can dual-boot two or more operating systems on the same hard drive, with each version of Windows or Linux - say - in its own partition. Here, though, we'll show you how to install another operating system in a virtual machine so you can start it up on your Windows desktop whenever you need it. No need to reboot, no need to have multiple hard drives or separate partitions. Plus, it's free!

What is a virtual machine?

A Virtual Machine is exactly what it sounds like. It's like having a second PC or laptop, but instead of being a physical thing, it's software. 

On a virtual machine you can run any operating system you like, so long as it's compatible with the virtualisation software you're using. It could be a second copy of Windows 10, but it could also be a Linux distribution or an older version of Windows.

The benefit of a virtual machine is that you can try out a new OS without affecting your files, or you can install and test apps without the risk of messing up your real Windows 10 installation.

You can also create multiple virtual machines, meaning you can run Windows 10, Ubuntu, Fedora and other operating systems and swap quickly between them.

Virtual machines (VMs) can be quite resource hungry, so you might want to avoid having all of those operating systems open at once, or your machine may slow to a crawl. RAM tends to be the main bottleneck for performance with VMs.

There are several well-known VM programs available, but probably the best place to start is with Oracle VM Virtualbox, which is free. The 64-bit versions of Windows 10 Pro, Enterprise and Education have Hyper-V built in which means you don't need additional software such as Virtualbox, but you may have to enable it first. Type 'Hyper-V' in the search box and then click on ''Turn Windows features on or off' if it appears. Then tick the box next to Hyper-V in the list.

How do I install a virtual machine on Windows 10?

First, you'll need enough free hard drive space to install the operating system of your choice. You'll also need that operating system, typically as an ISO file. If relevant, you'll also need a licence / product key for it.

Windows will generally work for a short period before it demands activation, but you could also download the Windows 10 Enterprise 90 day evaluation ISO which may give you enough time to do what you need to do.

Once you have your ISO file, download and install Virtualbox, which is the software we'll use here. It's a similar process in other virtualisation software, though.

Launch Virtualbox and you’ll be presented with a mostly empty menu welcoming you to the software. To create a new Virtual Machine you’ll first need to click on the New icon in the top left corner of the window. Next you’ll be asked to name the VM and select which type it is from the drop-down menus. We're installing Windows 10 here, but you can choose between Linux, BSD, Solaris, IBM OS/2, Mac OS X or Other (which includes DOS). 

How to install a virtual machine in Windows 10

After selecting your operating system and the exact version you’ll need to allocate the Memory size that the VM will have access to. VirtualBox will recommend an amount, and we suggest you go with that then click next.

Now you’ll be asked if you wish to add a virtual drive for the VM. Agree to this by clicking the Create button, then select VDI (Virtual Disk Image) from the list, click next, then select the Fixed Size option on the next page. Finally you’ll be asked to name the drive and confirm it’s size (again go with the recommended amount). Click Create to complete the process.

How to install a virtual machine in Windows 10

When the virtual drive has been created you can now begin installing your operating system. To do this click the Start arrow. In the window that appears (Select start-up disk) click on the folder to the right of the drop-down menu that appears next to 'Empty'. Here you can navigate to the Windows 10 ISO file that you downloaded earlier.

 How to install a virtual machine in Windows 10

Once you’ve selected the ISO click Start and the OS will be installed on your virtual machine. Once that's done, you can use your virtual operating system in a Window, just like any other app. To shut it down, click the File menu and choose 'Close' and then 'Save the machine state'. 

In some instances we have seen compatibility issues with certain PCs. Solutions range from needing to update the BIOS to disabling Hyper-V on your system. If you do encounter any errors, then the best thing is to enter any error codes into Google and hunt down the solution that is relevant for your specific system, as there would obviously be too many possibilities to list in this article.