Screen Brightness Question?

OK so i open the game Enemy Territory: Quake Wars on my PC and it automatically brightens my screen to fit the game. This time i hit Alt+Tab to open a recording program and i saw that my screen was bright, no big deal, it'll og back when i close the game, and it always does. This time, however, when i closed it with Task Manager it said the game stopped working and i closed it. the screen was still bright. i opened and closed the game normally but the screen stayed teh same. im not going to fix my monitor brightness, i want to know how to switch it back non-manually, so i can know how to anyway.