If you've lost your Windows 8 DVD or perhaps you just didn't get a physical copy when your purchased a new PC, then it is possible to legally download the full Windows 8 or 8.1 ISO from the internet. You'll need your Windows 8 serial number to get started - so don't lose it! First of all, navigate to this page on the Microsoft website and choose if you'd like to download Windows 8 or 8.1 by clicking the appropriate link and running the exe file: http://windows.microsoft.com/en-us/windows-8/upgrade-product-key-only Once it has loaded, you'll be prompted to enter your serial number. Do this and then click next. You'll then be shown a little information about the version you are downloading, as well as a note about metered internet access. Click next to continue. It will take a little while to download Windows 8, so sit back and wait for the download to complete. Once it has finished downloading, select install by creating media. Now click ISO file and then save. It will take a few moments to save the ISO to a location of your choosing. Click finish when you are done, or chose an option to burn the ISO direct to disc.