I bought Resident Evil 5 for the PC used from Amazon. Apparently, I only purchased the disc, without any of the paperwork. When I try to connect to Windows LIVE, it tells me to input my Product Key, which I don't have. When I click the option that supposedly gives me a product key, it opens the Windows LIVE client and doesn't do anything. What do I need to do to get a Product key for the game? Do I have to *buy* one, because if so then this will be the last Windows LIVE title I buy, because there's no reason for me to have to purchase a game twice. Thanks for the support!