Actovation code already used

I got the Hunble EA Bundle way back and I installed and played a little with Dead Space 3.  I didn't play it much bvecause at the time I had a **bleep** grahpics card.  Now that I have a good one, I tried playing it, but it says that I must put in a product key!  I ALREADY REDEMMED IT!  Now I cannot play it!