I just got the game Nocturne and I know it's old but I installed a patch so it works with Windows XP and the game runs fine except the screen flickers constantly to the point in which I can't play it for more than about three minutes before I get a headache and my eyes hurt and I have to quit the game. It flickers in the menu and during game play. How can I make it stop? I'm using a Geforce 6600 GT and have 768 RAM.