The Keyboard light is on but the screen is black!

when I press power on, the keyboard light will stay for about 5 secs and then is off, but the fan is still running. All these happen while the screen is pitch black, never shows neither a light nor blink, no logo display. Now, if I press power button one more time, the fan will then shut off, like it was never turned on.

Awkwardly, if I connect an external monitor, the external monitor will be also black. is it supposed to show "NO Signal" instead of Black? What type of issue is it? Video Card?

I have tried the NOVO button, F2, F12, etc. but nothing works

Please help. Let me know if my description is unclear!! thank you.