If the monitor settings are greyed out, they may not be applicable to the connection you are uisng. I have seen some options greyed out when using a DVI connection instead of VGA. Another cause may be that you need to enter an advanced mode to change things, read the monitor manual. Try an auto adjust on the monitor, that should be either a button or an option in the menu. But if you are using the native resolution on the monitor, it should not have any borders. Did you try any other connections to see how they work? Are you sure it's the right resolution for the monitor?
Before anything, I will say that no other setting increases the size of the screen I'm receiving. It's currently at its maximum. I've reset the monitor to factory settings and no change in anything. I had it working before, but it changed when I upgraded the software on my computer. So maybe I need to access those greyd out areas of my monitors settings.
My monitors native resolution settings are set to 1920.