Hi, I'm not sure what's going on with my macbook, but every one in a while about 2/3 of my screen goes gray, while the other 1/3 displays everything perfectly fine. This happens when I turn it on or wake it up after its been asleep for a while. It has occurred once while it was awake. Attached is a visual example of what I'm talking about. Sometimes everything returns to normal after its booted, and other times it doesn't go out. When it is running with the grey screen everything works fine, because I can open windows and if I guess right I can open up applications from the dock, and it eventually disappears after so many apps are opened, i sleep it and wake it up, or completely restart the computer. Any ideas of what's going wrong?