You can download and install a Windows 8.1 Preview ISO file to upgrade straight to Windows 8.1 if you’re still on Windows 7. However, we’ll assume you want to upgrade an existing Windows 8 system to Windows 8.1. Interested in learning unique features of Windows 8, read this before proceeding below.
If you’re using an English language version of Windows 8, your system language must be set to US English. You can find a full list of supported languages on the Windows 8 preview page— be sure to set your system to any of the supported languages. If you’re using another regional variant, like UK English, this program won’t install. Windows 8.1 is also not yet available as an update for Windows 8 Enterprise, only the standard and Professional editions of Windows 8.
After you run the updater, you’ll see an “Installation Complete” message that prompts you to restart your computer. Windows 8.1 isn’t actually installed yet. Just click the Restart Now button to restart your computer.
Log into your computer after it boots back up and you’ll see a “Get Windows 8.1 Preview for free” message on your Start screen. Click the Go to the Store button and you’ll be taken to the Windows Store, where you can download the Windows 8.1 update. When the final version of Windows 8.1 is released, all users will likely see a message like this one.
In case you happen to get into Windows 8.1 from the scratch, use the universal product key for Windows 8.1 installation is NTTX3-RV7VB-T7X7F-WQYYY-9Y92F as provided by Microsoft.
Click or tap the Download button as if you were downloading any Modern app from the Windows Store. Windows will download and install the Windows 8.1 update. It’s several gigabytes in size, so you’ll have to wait a while. After the download process is complete, Windows will install the Windows 8.1 update and reboot your system. The rest of the setup process will happen automatically.
Sign into Windows after the update process is complete and you’ll see a few screens asking you for settings.