You may need to adjust your screen resolution or your Nvidia settings a bit. Could you tell us what happens when you try to play fullscreen?
I'm currently running the same card and at one point had the same issue. Assuming you're on w7, just keep messing with those stretch/scaling settings. Also, try changing your monitor res down to 1280x768 and full screen it and see what happens. If it works, change it back and it should still work. It's also been a fix for me in the past for black screen and black bars. Also 1 last thing, run the setup in the mapleroyals folder and make sure your refresh rate matches your monitor, 30, 60, or 75. Sometimes it detects 75 for some reason, that's also happened to me.
Even when i change it to lower Res.. it still black screen. i still didnt understand how to change my refresh rate of my monitor.. thanks for the help
Sure thing. For the refresh rate of your monitor, there should be a setup.exe in the mapleroyals directory. Run that, and report back.