Has your roommate done any physical damage to your laptop? I mean, has he drop it off or has the laptop receive any kind of kicks or something? I also would like to know if there was a power outage in your area by the time the laptop went off?
The reason for your laptop to not be able to power on is that somethin related to your mother board, hard drive or power supply went bad. I think you should bring it to a technician for tests.