Black Screen on Boot after update (iMac)

My iMac said i needed to restart for updates, so i did. It was doing its thing, i saw the white update screen downloading so i walked away to make some tea, 20 minutes later i check on it, the screen is black, so i move the mouse and hit the keyboard to wake it up... nothing. So i figure it must still be updating so i leave it sit for 30 more minutes. I come back and the screen is still black. So I forced powered it down, booted back up, and still has a black screen. My keyboard normally lights up, but it wasn't anymore, no keypresses or anything was working. I also tried a different keyboard and nothing as well. I tried restarting several times and still just a black screen. I reseated the ram, and that didn't help. Kind of at a loss of what to try next?! I had the same update pop up on my macbook today and i quickly cancelled it because i don't want to lose my only computer now! Help is appreciated! I'm not sure what model it is, but it has to be around 2011-2013, 27" screen that you could remove the ram from the access panel.