Under Reset this PC in the right pane click Get Started.
In the resulting Update & Security window, click Recovery in the left pane. To begin, in the Start menu, click Settings, and then click Update & Security. How do I restore laptop to factory settings?
You now have an installation medium that you can use to reset Windows 8 as described in the section “Instructions to reset Windows 8 without losing your data”.
To do this, simply follow the instructions in the installation manager. From the list, select the file “Windows-7-USB-DVD-Download-Tool-Installer-en-US.exe”, click “Next” and save the file on your computer. Select the language “English” and click on “Download”. Next, you need the Windows 7 USB/DVD Download Tool in order to create a bootable data carrier. Select the right version (32-bit or 64-bit) and download the file.