Laptop does not power on

I dropped my Dell Precision and the screen flickered and went blank (LCD still on) power button had no response so I took out thr battery noe and the power button light turns on for 16 seconds and turns off the fans doesn't spin and the screen doesn't turn on but the LED status shows power and battery (there's no battery inside) I reseated every cable and ram and gpu and still nothing I tried to connect a external display and nothing I also did the power drain thing where you disconnect every power source and hold down the power button