Well... thank you for your detailed help m1ch43lzm but those procedures are too complex for someone that never did it before and things could easily go wrong.

If there's no other easier method like preparing a crisis USB disk and using it to recovery, unfortunately I will have to take it to the store were I bought it or to try to directly contact Lenovo. Maybe the can manage to fix it without messing with the SSID or maybe they allow me to take it before (I suppose that by default should void the laptop warranty).

Hi guys, My wife's laptop got into the same situation as most of you are describing here:

Lenovo IdeaPad 3 15ALC6 type 82KU with SN PF4F7VP3.

Symptoms when you turn it on with the power button:
1) The monitor goes black. There seems to have some very slight light, but it's black.
2) The LEDs for the following buttons remain on steadily: Esc, Caps Lock, Num Lock, Power.
3) If you connect an external monitor via the HDD, it doesn't detect a signal.

Before the problem occurred, automatic updates were performed, but since they were made automatically,...