I found an iMac in the middle of a busy street a while back, and grabbed it to hopefully return it to its owner, but unfortunately the screen was completely ruined since it had likely fallen off a car going 50 mph. I figured I could just hook it up to an external monitor to see the name on the screen and see if I could find a way to contact the person, but nothing has been showing up on my external monitor. So I figured MacBooks must have some kind of feature where you can’t see the screen until logged in? How do I get into the computer without seeing the screen?