Thanks for your help.
I'd rather not clutter up the top of the forum with too many stickies, but it's good to have this info because when someone does post again with the same problem, we can refer them to this thread. It's strange that this problem is suddenly cropping up for so many people, because the game is several years old.
Of course, I'm taking it on faith that everyone is using this solution on LEGAL versions of Black Mirror.
Remember we don't support piracy here - but I know sometimes a no CD crack is the only way to get a legal version of a game working (which is pretty screwy).