A couple of weeks ago I purchased Crysis Warhead. At that time I installed it, put in serial number, and played it for a little while. Since them I had a hardware failure and upgraded motherboard. Also had to reinstall windows Vista. I think overall I reinstalled Crysis Warhead twice in the process of rebuiliding my system and installing a new operating system. Last night when I reinstalled Crysis Warhead, the following popup screen appeared - " The game will not start! For security reasons, only a limited number of machines can ever be licensed by a single purchase. This limit has been reached. Please purchase another registration code, reinstall, and then try again". I tried emailing EA customer service but have not had a reply. The game is worthless and I just purchased it a couple of weeks ago - I wish I had never purchased the game at all. I knew nothing about the DRM limitation when I purchased it. Beware! You may find yourself in the same predicament as me if you purchase this product and make hardware changes.