These are instructions on how to flash stock ROM (firmware) on Google Nexus Device using the Windows Computer.
Requirements: Your Google Nexus device should have at least 20-30 percent of battery to perform the flashing process.
(Developer Options are hidden for Android 4.2.2 and above. Go to Settings > About Phone > Built Number > Tap on it 5-8 times to display this option).
Step 10: Once, Command Window is launched, Give the following command: fastboot oem unlock
[*] Caution: Flashing the Stock firmware will delete your personal data, so take a backup of your personal data before proceeding.
[*] Google Nexus Pixel Stock Firmware: If you are looking for the original firmware for your device, then head over to Download Google Nexus Pixel Stock Firmware page.
[*] Google Nexus Pixel USB Driver: If you are looking for the original USB Driver for your device, then head over to Download Google Nexus Pixel USB Driver page.
[*] Credits: The above flashing instruction is provided by Google at the Factory Image for Nexus Device page. We made the instructions more noob friendly.