MacBook Pro will not turn on

You are in a pickle! Sadly, it does sound like your logic board has died.

You didn’t state it but I think you’ll see your MagSafe plug is glowing green and your battery checker LED’s (8 of them) are all lit and steady. If I’m wrong please correct me.

This series does not have a dedicated graphics chip which would be beneficial working in graphic design. None of the 13” Unibody or Retina series offered dedicated GPU’s. If you are doing deep and large drawings I would recommend you get a 15” with a dedicated GPU. If you are just doing small to medium sized simple line drawing or shallow colored drawings you likely will get away without it.

So what to do? Here’s the IFIXIT guide to replace your logic board: MacBook Pro 13" Unibody Mid 2012 Logic Board Replacement as you can see its a bit of work. Here are the two possible logic boards MacBook Pro 13" Unibody (Mid 2012) 2.5 GHz Logic Board & MacBook Pro 13" Unibody (Mid 2012) 2.9 GHz Logic Board

Jumping to a newer system will be costly! Even another Unibody model. If you can find a 15” 2012 model I would jump onto it as you will be much happier in its performance and you can swap out your RAM and drive over if need be.

If you find the older display is lacking then jump to a 15” 2013 or 2014 retina model but that would be the most costly and you need to buy the larger RAM (16 GB) upfront as its soldered to the logic board.