As Bert says, after installing Win 10, you still have the old operating system retained (labeled windows.old in the files). Shut down your computer by turning it off (press and hold the power button on the computer case itself, if needed). When you push the power button again, you should eventually arrive at a window that looks like this:
![[Linked Image from amazingcharts.com]](http://amazingcharts.com/ub/attachments/usergals/2015/09/full-636-755-screen_shot_2015_09_09_at_9.57.33_pm.png)
