Windows 8.1 brings you the Windows Store, Start screen and Microsoft account, but also enhancements in personalisation, search, Store apps and cloud connectivity and the security and reliability features you expect from Windows.

To upgrade to Windows 8.1 from Windows Vista or Windows XP, you'll need to install it from a Windows 8.1 DVD and perform a clean installation. This means you won't be able to keep any files, settings or programs when you upgrade.

Visit Microsoft for the detailed tutorial.

Also read: How to upgrade Windows 8 to Windows 8.1