How to roll back Windows 10 to Windows 7 or Windows 8.1
Here are the instructions to roll back to Windows 7 SP1 or Windows 8.1 Update from Windows 10.
It’s worth pointing out that you won’t see the option if your system in unable to roll back.
Remember that you only have one month to revert back from Windows 10 to your previous version. Here is more info: http://pureinfotech.com/2015/08/10/windows-10-one-month-roll-back-previous-version/