15 R3, LCD screen is extremely dark

I am using a 2016 released Alienware 15 R3 model. After installing Windows and during the first login, the screen appears extremely dark. When I connect an external monitor via HDMI, the screen on the external monitor is displayed normally. However, the laptop screen remains extremely dark.

At first, I thought the screen was black, but I could faintly see something moving on the external monitor along with what I was doing. I have to shine a flashlight on the laptop screen just to barely notice any movement (making it difficult to use).

The graphics card drivers are all updated to the latest version, and there are no conflict signs in Device Manager. I have checked multiple things:

• Brightness is set to the maximum.
• The display is in duplicate mode for internal and external monitors (when in extend mode, the internal monitor is too dark to adjust any settings).

When the UHD graphics is disabled: Internal monitor = completely dark, external monitor = visible.

When the Nvidia graphics is disabled: Internal monitor = visible, external monitor = not visible.

When both are enabled: Internal monitor = completely dark, external monitor = visible.

In Windows safe mode: Internal monitor = visible, external monitor = not visible.

I want to be able to see both the internal and external monitors properly and use them in extended display mode.

How can I fix this issue? Please help me with this problem.