This apply only to Nvidia users though i'm sure Ati have a similar thing.
Goto 'Controle Panel' click 'NVIDIA controle panel' then just follow the picture below.
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If you find the grass or general scenery too colorful , adjust the 'Digital Saturation' I made it lower and now all the games look better. How people see colors are all different depending on how you have the screen setup in the first place , it is not necessarily any fault of the developers ad over saturated images.