Hey Everyone, Over the last couple weeks, the screen on my MacBook Pro (purchased July 2011) has started turning black/going to sleep whenever I open my laptop. The problem can be fixed if I press one of the brightness keys (sometimes) or by unplugging the laptop. Indeed, the problem only ever occurs when the laptop is plugged in (it works perfectly fine when not). Does anyone know how I can fix this? The laptop still turns on and I still see the log-in screen for a couple seconds before it goes black. Thanks!