I bought a used macbook pro for school last year and it was refurbished and totally fine, no problems. It's probably like 5 years old. Then the other day the screen started flickering out of nowhere then went to colored verical lines. So I shut it down and restarted it. It starts up with the chime and goes to some check up page with an apple and a progress bar. The progress bar goes about 2/3 the way and just stops and sits there and won't do anymore.