Bad motherboard?

So randomly a couple of weeks ago my screen just stopped working. Whenever I turn it on or wake the screen white and green flashes. I've reset it to stock, and tried just about everything else I could. I just got my new digitizer in the mail thinking it was that, and it doesn't work. I know the phone is on because I can see the notification light flashing. I'm not sure what else to do but return the digitizer and try replacing the motherboard. Is this what could be it? Could it be something else? Thanks.