If you unknowingly bought a product which had been used as showcase unit from a dealer, what would you do?

I bought a digital camera from a dealer. The sales person said that it's a brand new product. Later that, I found out that the camera had been used as a showcase product in PC Fair. What can I do as a consumer? Is it possible to ask for a replacement for a new one?

As long as you have the receipt, and, trade it for one just like it, the store should be obliging.