If the fan is spinning loudly it may be the thermal sensor on the LCD screen on the rear was not replaced from the old unit. Without it, the CPU runs at 0.8ghz and the fan spins at full speed. As for the black screen, likely a cable was not properly connected. I’m thinking maybe the power connected was not seated well and if the thermal sensor WAS attached, it and the screen itself doesn’t receive any power hence, black screen, and full fan.