I had someone over at my house, and I let him play the halo ce campaign for a bit. He came down and told me that the level screwed up, the screen wold go black, then restore a few seconds later. When it restored, it had horrible lag, and the screen went black again. He said that he just was killed by an elite, and as soon as he respawned it started. I went up to the computer to take a look, and the screen was black, and there was some error on the screen. I rebooted the computer and loaded halo again. I loaded the campaign, and the screen was black again. I tried using map_name to switch levels,and I got an exception.

Any help?

Make sure your grahpics card has anti alising off, if it is on turn it off and vis versa. Also if that dosent work try reinstalling the game.