1. Go to the search bar in the lower left corner and type "reset." Then click on "Reset this PC" that you see in blue below. 

2. This screen will pop up and click on "Get started" (in grey) that is under "Reset this PC" 

3. Click option 2 "Remove Everything" and it will run and remove anything that wasn't on the computer when it came from the factory. Follow the instructions on the screen after this. Your computer may restart a few times in the process. Make sure it is plugged in and let it run.