Step 1:Make sure your Surface is shut down and plugged in.
Step 2:Insert the USB recovery drive into the USB port.
Step 3:Press and hold the volume-down button while you press and release the power button.
Step 4:When the Surface logo appears, release the volume-down button.
Step 5:When prompted, select the language and keyboard layout you want.
Step 6:On the Choose an optionscreen, select Troubleshoot > Recover from a drive.
Step 7:If prompted for a recovery key, select Skip this drive at the bottom of the screen.
Step 8:Choose either Just remove my files or Fully clean the drive.
The option to clean the drive is more secure but takes much longer. For example, if you are recycling your Surface, you should clean the drive. If you are keeping your Surface, you just need to remove your files.