PERMANENT Black screen on 2015 Macbook Air

My 2015 Macbook Air, my newer one, (I am using my old one now) has a black screen, unchangeably black. I have tried the things that don't require being able to see anything on a screen, like trying to reboot ( Shift+Control+Option+Power button at the same time for a few seconds, then Release all keys at the same time, then boot the Mac as usual),

which seems to be the same thing if one wants to reset the SMC (system Management Controller). Now, on top of the screen continuing to be black, the bottom half of the laptop (ie, the side where the keyboard is) seems to be vibrating at a very high speed!

Also, I have tried: Once I hear the chime, even though I don't know if I have turned the thing off, or if has been turned on, I type in my password as if I were actually looking at a normal screen. Doesn't have any affect.

Since I have a black screen, I certainly cannot boot in safe mode, as, I cannot click on anything, or type anything at the right time, I have nothing on the screen. Nor can I offer my serial number, or any current info about the hardware or the software, as, I cannot read anything on the screen.

Nothing seems to improve the situation. I seem to be going in circles.

I cannot get help from apple genius without proof of the serial number.

The last successful thing I was doing on that Macbook Air, I believe I was just looking at things on the internet, and at one point/moment, I realized everything had frozen, so I pushed on the power button until the Air shut down. I did not do anything more for a couple of hours, as, I was wasting time anyway. When I tried to turn on the AIR again, I opened it up, and waited for the screen to show the login window. I only had a black screen, no matter what I tried, for over an hour.

So then I switched to my old computer and started the research. After doing all of the above, with no success, nor even any progress, I am hoping someone out there will read this and help me out.

Thanks!! Feb. 27, 2018 around 8PM Atlantic Time.