Today, I tried to wake my 2012 MacBook Air (8GB RAM) from sleep mode but nothing showed up on the screen even though I could hear the fans running. The screen was blank for a good 10 seconds or so, so I held down the power button to turn it off. After I turned my Air back on, my wallpaper automatically switched back to the default galaxy/space wallpaper instead of the one I'd set. Besides that and the fact that a RAMDisk that's supposed to auto-create after each boot up was not auto-created, everything else seems fine. Any idea why this happened? And sometimes when I shut it down, it takes a good 10 seconds to shut down with dock only disappearing halfway. Thanks!