How do I use my Nvidia promotional codes???

[dpodblood]

So I just received my new GTX 570 which came with 3 promotional codes. Mafia II, Just Cause 2, and 3DMark 11. Maybe I am just missing something obvious but I have no idea where I'm supposed to enter these codes. All the pamphlet that came with the card says is "use this promotional code when you check out." Check out of what? I tried the Nvidia store, but the code for Mafia didn't work, and Just Cause 2 doesn't even exist in the Nvidia store. Anyone here have experience with these promotional games? (Apologies if this isn't the right forum.)

 

[OILFIELDTRASH]

Steam.

 

[dpodblood]

Ah I tried that, but I must have entered it wrong the 1st time... I've got Mafia II activated now... Case closed...

Derp.

 

[slyy1024]

I got the promo code with new laptop (with 580M), but didnt have fast enough net to download these 20+GB.
Now 9 months later, it is expired.

Do you know who to contact? Seller can't help me.