Screen has a shade of gray over it! NEED HELP!

I was playing Battlefront II when all of a sudden it stopped responding, so I shut it down with task manager. But after that I noticed that my whole screen has a shade of gray over it. I had noticed this happening during the loading screen of Battlefront II, but had thought nothing of it since it always turned back to normal after a minute. Now however it is like this all the time, except for when playing a game in fullscreen mode. It is not a monitor problem since it looks normal with my playstation. I have seen a few similar problems around, but no real fix. If anyone knows how to fix this or if it's even possible please let me know.