6. Burn the ISO image you downloaded in step 2 to a DVD. If you're running Windows 7, it's simply a case of double-clicking on it to launch the Windows Disc Image Burner tool. If you have Vista or XP, we recommend CDBurnerXP from cdburnerxp.de.
7. Reboot your PC and leave the DVD in the drive (or insert it into the drive of the computer onto which you want to install Windows 8). If your computer doesn't boot from the disc, reboot again and enter the Bios. Look for a 'boot priority' menu and put the CD/DVD drive at the top of the list.
8. When the PC has booted from the DVD, follow the instructions and enter the product key DNJXJ-7XBW8-2378T-X22TX-BKG7J when prompted. Click Install Now to proceed. Don't choose Upgrade installation but click Custom install. Make sure you choose the new partition you created, so you don't overwrite your existing Windows setup.
9. The installation process will reboot your PC several times and will eventually boot into the new Metro user interface with its colourful tiles. For a guide on navigating around this new and unfamiliar desktop, see our complete guide to Windows 8.