OK so I bought the Witcher 1 on steam two days ago because it was on sale and I want to play through both games before Witcher 3 comes out. After I finished downloading them I began playing Witcher 1 and a window came up saying that I have a product key that I have to enter in the game at one point. I copied down the key and began playing. I'm already up to chapter 1 already and there is still no place to be found where I put this key in. Can someone tell me what this product key is for? Where do I use it? Do I use it in the game at all, do I use it on another website, somewhere on steam? If this product key is not used at all, will I still be able to transfer my Witcher 1 saves onto Witcher 2?