Microsoft on Wednesday kicked off its annual Build developer conference by making a free preview version of its brand new Windows 8.1 operating system available to download. Any current Windows 8 users can simply go to Microsoft’s Windows preview website and download the new update for free. Highlights from the new operating system include the return of the Start button (sort of), enhancements to desktop mode, changes to the Start screen, multitasking enhancements and more. The update is available immediately and can be downloaded by following the source link below.