Laptop Not Displaying on External Monitor

Hello,

I recently broke my laptop screen through an unfortunate accident. Their was an internal crack in the LCD and the screen was different colors. After bringing it to a repair place, he was unable to install a new screen because the backlight wouldn't function.

Anyway, I decided to keep the laptop but hook it to an external monitor. However, when I turn the computer on, both the laptop screen and the external monitor display nothing. If someone could please help, I would appreciate it.