A user turns on their laptop.

When the keyboard backlight turns on, the laptop is receiving power and at least partially completing its startup hardware initialization. A black internal display can be caused by multiple issues, including a failed LCD/backlight, a loose or damaged display cable, an incorrect display output selection, or a graphics subsystem problem. The best next troubleshooting step is to connect the laptop to an external monitor because it quickly isolates whether the problem is with the internal display assembly or with the system’s ability to generate video at all.

If the external monitor displays video normally, the GPU and motherboard are likely functioning, and the technician should focus on the laptop’s internal screen components such as the LCD panel, backlight, display cable, or connector seating—often accessed by removing the bezel only after confirming this. If the external monitor also shows no video, the issue is more likely related to graphics output, memory, motherboard, or firmware/POST problems, and further internal diagnostics are required. Plugging in a charger is reasonable if the device seems underpowered, but it does not directly test the video path. Replacing the laptop is not an appropriate “next step” in troubleshooting.