How to Upgrade to Windows 8.1. See in this video how to upgrade to Windows 8.1 from Windows 8. Quickly see Windows 8.1 download and install steps from the beginning to the end. Windows 8.1 update for existing Windows 8 users is located in the Windows Store for easy download, upgrade and install. Upgrade quickly from Windows 8 to Windows 8.1 as is seen in this easy to watch video tutorial.