Press and hold down the power button for ten seconds to switch off your machine. Next, press and hold the 0 key and, at the same time, tap the power button once to switch on your PC. When the machine starts beeping, release the 0 key.
A warning message will appear on-screen, prompting you to verify your system recovery. Select Yes to continue.
Next, select the Recovery of Factory Default Software option, followed by Next. Then choose Recover to out-of-box state, and click Next once more to start the recovery.