Monitor settings, won't help too much, I mean at all..
think of it this way, when he said making it windowed mode made it brighter.. if you closely suss out what he said, he made windowed mode = small res = more pixels per square = better brightness. my screen has like 8000:1 or the other way i removed the sticker ages ago, but that was the brightness, now that's for a 1440x1000 screen, if the thread starter had the same screen reso and made it windowed to lets say 800x600 there would be more brightness in that square then the whole screen, the whole screen stretches it while windowed mode compacts the full brightness into a small size making it more brighter not a lot, but very noticeable.
If i try to edit the config_mp.gsc file at all, it will jus reset the first time u start the game. I posted the same issue on aIW forums but no 1 gave a sh*t and was to nooby to answer me. The admins jus arent looking thru their forums enough.