Try this...
1. Shut down your computer, from the start menu. Not hibernate or sleep, but actually turned off.
2. Disconnect any and all external devices from the laptop. Mouse, keyboard, thumb drives, WiFi cards, USB hubs, Bluetooth adapters, monitors, etc.
3. Now make sure your laptop is connected to the power adapter cord.
4. Turn on the laptop and 'Immediately' press and hold down the "0" (number zero) key at the top of the keyboard.
5. Stop pressing the key when you get a warning message on the screen.
6. If, by chance, the recovery process asks you what OS you are wanting to load, make sure you choose the correct one.
7. You should now get another warning message letting you know that all personal data will be deleted from...