For most people, running one operating system on their PC or laptop is enough, but in some instances it can come in handy to have two separate versions on a PC. This may be due to specific software that only works with an older release of Windows, simply preferring the way one works, or just wanting to compare the differences between Windows 7 and Windows 10 before committing to an upgrade. Thankfully Windows is designed with dual-booting in mind, and in this feature we explain step-by-step how to dual boot Windows 7 or 8 and Windows 10.

You can create this dual-boot system from pretty much any version of Windows, but for this tutorial we will add Windows 10 to a PC running Windows 7. 

See also: How to get Windows 10 now and Should I upgrade to Windows 10?

Before you begin

Obviously you’ll need a copy of Windows to install, and this should be either burned onto a CD or USB stick. Microsoft provides a downloadable version of the Windows 10 ISO on its site, although you’ll still need to activate the OS if you intend to use it  permanently. To turn the ISO into a bootable version you should use the Microsoft Windows USB/DVD Download Tool.

dual boot windows 10

As you’re installing an operating system we recommend you do a full backup of your data, as there's no guarantee something won't go wrong and you wouldn’t want to lose precious files. 

How to dual boot Windows: In brief

  1. Create a new partition on your hard drive using the Windows Disk Management Utility.
  2. Place the DVD or USB containing the new version of Windows in your PC, then reboot the machine.
  3. Install Windows 10, being sure to select the Custom option.
  4. Select the newly created partition as the destination for Windows 10. Then click Next to install the operating system.

How to dual boot Windows: In detail

Creating a new partition:

Before you can install Windows 10, you’ll need to make space on your hard drive. This can be tricky if you’re running low on storage, as Windows 10 ideally requires around 20-25GB. Here's how to find and delete large files taking up space. Once you’ve backed up any files that are important you’ll need to go to the Windows Disk Management utility. To do so hold down the Windows key and press R. This opens a box, into which you type diskmgmt.msc and press enter. 

You’ll now see a list of the partitions on your hard drive. Select the primary partition, usually called (C:), and then right click to open up the contextual menu, from which you need to select Shrink Volume.

Now you’ll see another window that shows you the size of the partition, and asks you to Enter the amount of space to shrink in MB. To create a 25GB partition you’ll need to enter 25000 then click Shrink. This will modify the partition, allowing you the space you need to install Windows 10.

dual boot windows 10

Installing Windows 10

Place the previously created CD or USB version of Windows 10 into your PC and reboot the machine. You should be taken straight to the installation process, but if your machine goes back to your normal operating system straight away you’ll need to adjust the boot sequence in your BIOS. Check out our guide on How to enter the BIOS to help you achieve this.

When the install sequence starts you’ll need to select the Custom option.

dual boot Windows 10

This opens up a panel which asks you Where do you want to install Windows? From the presented options select the one entitled Unallocated Space, which should be 25GB. Click Apply and once Windows has created the partition click Next.

Now the installation process should go through as normal, and when you reboot your machine you will have the option to choose between the two operating systems. The bonus is that as different versions of Windows still use the same file system, you’ll be able to access your files from either OS.