Need for speed Shift, Shift 2, Undercover

Hello, I have the following problem: I have NFS Undercover, Shift, and Shift 2 in my library, but they won't download and I get a message asking me to purchase the game. I installed it from a DVD-ROM, but when I launch the game, I get the message: "The game can't start due to problems on our end." I understand the activation key limit has been exceeded. Can you reset the game?