I can't believe that afer progressing halfway through the game with absolutely no problems, I'm having all sorts of problems now.
Sometimes I can save my game, other times it just freezes mid-save. I have to get completely out of the game (almost to the point of rebooting my computer). When I try to restart the game, a message comes up asking if I want to reactivate. I am using a disc, not a download. I have to open the DVD player and close it again for it to recognize the disc.
I've also ended up with a dark blue screen and nothing else, not even a curser (Windows 7 version of the BSOD?)
I don't even know where to begin to get playing again, because all this is happening at the same time. I thought maybe it was a particular part of the game, but I got through a little further and then it just froze at the save again.
Any suggestions?

I've had similar issues saving the game - try lowering the graphics settings a notch (those under the Graphics Setup section under the in-game Options). Mine would hang with a white screen for the saved image.

As to the reactivation message, maybe the disc is smudged? It may need a good cleaning.

My disc is pristine, so that can't be a problem.

I'll try changing the graphics setting tonight after work. But I'm puzzled as to how it could make a difference now since the first half of the game played flawlessly.
I'll post here my results.

I lowered the graphics settings to "normal". I did fine last night saving and loading. I hope it lasts me through the game because I'm enjoying it and hate to leave it in the middle.
Thanks for the suggestion.

Sorry to say, game froze when saving...again. I thought I had this licked. I'm going to see if I can just stumble along til the end.