One day, my grandma came to me with a macbook pro retina from 2012 and said, “When I turn It on, the display remains completly black. But If I hold the power button until It shuts down, and then I turn it on again, It works. They said the GPU is broken and it will cost 800 bucks to fix. It’s not worth It. I’ll buy a new MB instead. I’ll give you the old MBP and If you can fix it, It’s yours.” Challenge accepted…