I just bought a used macbook pro from someone and the monitor randomly turns off and I have no idea how to turn it on. It seems to do it after I've been on the laptop for more than 30 minutes. I've been monitoring the temperature and the cpus and they both seem fine. 1) Has anyone heard of this problem before? 2) How do you turn the monitor back on? I know that it's the monitor turning off and not the laptop because the lights on the keyboard will still be on. Also, I hear the laptop turn off after I hold down the power button to turn it off, which is the only thing I know do do. I hope this is easily fixable because I don't want to return it, I'm enjoying it too much besides this problem.