[quote][b]Posted by:[/b] wazups2xs Both Halo 1 and 2 have terrible mouse acceleration so I can't play either of them.[/quote] You can do what Btcc said (though I keep vsync on, as massive horizontal tearing screws me up far more than a constant 75 FPS does), or you can automate that process by creating a CFG file in your Halo directory with the text "mouse_acceleration 0" and add the command line argument "-exec mouse.cfg" to your Halo shortcut.