So I was just browsing the internet and my rMBP's screen went black and turned itself off. I now cannot turn it back on! It's been plugged in to the charger all day, so the battery definitely isn't dead - also the green light is showing. I've tried holding down the power button for about 30 seconds, holding down shift,ctrl, alt and power to try and reset SMC but nothing happens. Been about 30 minutes now and still nothing. Is this indicative of a logic board failure? It's obviously still under warranty so shouldn't be an issue if it is. It's a 15" 2012 base model (256SSD, 8GB RAM). The screen went black a couple of times throughout today but I thought nothing of it, assumed I just needed to SMC reset. Was this an early warning sign telling me my logic board was on it's way out? I've booked myself in for a genius appointment tomorrow anyway.