My computer hasn't been off or asleep for a while. I have been downloading. I was just using Handbreak for the second disk of a season, when, suddenlt after changing disks, my Mac froze and a weird alert came up telling me I have to shut it down, and to hold the botton, ect. I boot it up and now my battery meter is 6% lower, at fully charged? It's stuck there now. What is happening?