then your computer is messed up. If you changed your in game settings, your monitor might be too dark. If thats not the case, it may be some sort of driver issue or a setting that just does not mix well with your driver/card.
I will more likely than not be downloading it again soon. Good to know that they fixed alot of stuff. I think the worst part before was shooting something in the head, and it not registering as a headshot...