The color on my monitor looks blueish green

I recently changed my screen resolution on my dell 17 inch desktop. Now everything fits on one screen but my color looks a blue greenish color. my resolution is set on 1024 by 768 pixels and the color quality is on 8 bits and i cannot change the color quality because the slider is greyed out. I have done everything I can think of. I don't want to go back to the old resolution because it makes everything on the screen huge and I cannot see everything that I need to see. PLEASE HELP!!!!!!!