To remove all data from a laptop and reinstall Windows, boot into the recovery partition on your computer, and follow the on-screen instructions to reset the device to its factory state. Windows 8 and later systems also include a built-in factory reset option accessible through the PC Settings screen.
The process of booting into the recovery partition of a laptop varies from manufacturer to manufacturer and typically involves hitting one of the function, or "F," keys located along the top of the keyboard immediately after turning on the device. MSI laptops use the F3 key for this purpose, Samsung devices use F4, Dell and Alienware use F8, Sony uses F10, and HP and Lenovo use F11. On the other hand, Acer laptops require you to hold down the Alt button and press F10 to achieve the same effect, whereas Toshiba laptops assign the 0 key to the job.
On Windows 8 or newer systems, enter the PC Settings by clicking Settings in the Charms bar and selecting Change PC Settings. Click the Update and Recovery menu item and then select Recovery. Click Get Started under Remove Everything and Reinstall Windows to start the factory reset process.
Some laptops might not come with a recovery partition. In such cases, a recovery disc usually comes bundled with the device. If your device requires you to use a recovery disc, insert it into your CD or DVD drive and restart the computer. The laptop should boot into a recovery utility with the option to reset your computer.