Have you ever had headache while playing a game? Did you ever noticed a low refresh rate in your game? Here is a solution how to change it.
1. Select Start > Run, and type "dxdiag".
2. When the dialog appears find the last tab, and click "Override" (or somthing similar).
2. Just type your Value (be careful, dont type a value that your graphics card or monitor can't do!). Click Ok, and that is it!
Remember you changed the refresh rate only for DirectX Applications, not for OpenGL.