I don't have a external monitor or a hdmi or anything like that but I did the take out ac adapter and battery and then I plugged one it at a time so without the battery the screen stays black but power button works and with battery as we'll it stays black and power button doesn't work
Ok, if your laptop start up like you said, you can go to the BIOS, the startup noise is the fan you hear. The power button is just a step to power up the laptop. You have more steps after for the laptop to boot. So I don't think the problem is the black screen, your laptop doesn't boot at all.