Can't change displays refresh rate

I'm using OS X 10.8.3 and I want to change the refresh rate of my display, but I can't. When I go to System Preferences-> Displays, I have two options for resolution: Best for Display and Scaled. The first one is default. A little bit lower, I see the Refresh Rate option at 60 Hertz. When I click it, I can see there is also a 75 Hertz item there, but it's greyed out and unavailable. If I change Resolution to Scaled, then I'm presented with a list of resolutions I can pick. For some resolutions, 75 Hertz is available, but then another problem arises - the entire screen becomes stretched, so there's no point of using 75 Hertz with it.

How do I change the refresh rate without stretching the screen from a Mac Mini MD387 and display LG E2242T?

Solution 1:

To use that refresh rate you would have to lower the resolution to a maximum of 1280x1024. See the manual, page 29.