Too Dark games

I have a 32mb Geforce 2 card-I do not understand how I make adjustments to increase brightness/gamma-I have gone thru the display settings and adjusted the setting under opengl for gamma-I have also been able to save it-but when I close the dialogue box my desktop reverts back to its default setting-How does the game pick the fact that the saved setting is meant to be used by it-by name ? How do I name it Wolfenstein ? return to ?