Hey if you are still looking at this I might be able to help. Are you running windows XP, Vista or 7? I recently purchaced it for PC. I could start the game normaly and after a short amount of time the screen would freeze. I could however still hear the music in the background. After awhile I Googled about it, to find that it has issues when running on Windows 7. There are a couple of videos on youtube about fixing it. They have helped, and my Fallout 3 hasent frozen since. But if you have just "cheated" to get the achievemnt's then I suppose you are not intreseted in the game.
Oh Herro! I rike praying games!