Microsoft has announced that Service Pack Support for Windows 8.0 will end today, January 12th, 2016. Windows 8.0 is the version released in 2012 without the Windows Start Button in the lower left screen portion. More information is at https://support.microsoft.com/en-us/lifecycle?C2=16796.
Windows 8.0 users should upgrade to either Windows 8.1 or Windows 10.
Windows 8.1 Upgrade FAQ: http://windows.microsoft.com/en-us/windows-8/upgrade-to-windows-8
Windows 8.1 Upgrade Tutorial: http://windows.microsoft.com/en-us/windows-8/update-from-windows-8-tutorial
Windows 10 Upgrade FAQ: http://windows.microsoft.com/en-us/windows-10/upgrade-to-windows-10-faq