New mac user - had this thing three weeks. I was trying to use "terminal" to make files visible. I got an error in the terminal window, and couldn't type in any commands. So I figured I'd just restart the computer to clear out whatever oddness was causing that. It won't reboot. Can't get to where it forces me to put in a password to log on. What can I do? Returning it is high on my list, but I need to at least recover the work I've done on it in the past few weeks.