Hi there !Please halp somebody ! How to change background on AutoCad 2014 (global)

Are you talking about the background seen in model space or in paper space?  Both can be changed via Options > Display > Colors.  Look at 2D Model Space > Uniform background and Sheet/Layout > Uniform background and Paper background.Now if you are talking about the color schemes for AutoCAD there are only two: dark and light.

Thank you !