Users that wish to rollback to Win 7 / Win 8.1 can use the Windows 10 recovery option found in Settings.
To access this feature:
- Open the Start menu and select Settings.
- Click the “Update & security” icon and select “Recovery.”
- You should see a “Go back to Windows 7” or “Go back to Windows 8.1” option.
- Click the "Get started" button to remove your Windows 10 install and restore your previous Windows install.
There are a few caveats to note before you take action.
- The update to Windows 10 must have taken place within 30 days.
- This OS will be "de facto" soon and part of Windows updates.
- You should consider backups with Crashplan both before and after rolling back your machine to the prior OS.
For instructions on how to use the built-in rollback option, visit the Official Microsoft Link found at : http://windows.microsoft.com/en-us/windows-10/going-back-to-windows-7-or-windows-81