I have the same exact problem!!! And i bought it from a store and it was sealed!! Someone tell us what to do or we will start advertise war with lucas arts! And we do not want this! You can not sell us problematic cd keys!
I have the same problem... I bought the game a few years ago and it started to say "Your cd key is not authorized to play this game" a few days ago.
That's why i bought a new game, i just received it today and used a new and fresh cd Key !
But guess what, "Your cd key is not authorized to play this game"
this is really annoying, cause i do really like this game ><.