Dell XPS L502x strange speaker sound

Hi. I have bought a Dell XPS L502x , and short after, I discovered that it has a very strange problem.

Out of the blue, is starts making a strange sound from the speakers, and it won't stop until you press F11 or F12 (lower volume or higher volume). After pressing one of these keys, the volume goes on mute.

Also, while it makes this sound, you can't do anything on the laptop. Can't move the mouse, can't type, nothing.

I have tried Windows 7 and Windows 10, with the audio drivers that Windows installs, and the one from Dell's website, but the sound is still there.

Any ideas ?

Here are 2 videos with the sound.

https://youtu.be/4eDRrfM7GDo

https://youtu.be/IanIEC2SyoU