If, for some reason, you need to change your Unreal Tournament 3 (III) serial number, I have an easy way to do it. Here goes: Browse to the Unreal Engine configuration file found at: C:\Users\YOUR_USER\My Documents\My Games\Unreal Tournament 3\UTGame\Config\UTEngine.ini Open the file, and near the end you will see this header: [OnlineSubsystemGameSpy.OnlineSubsystemGameSpy] Beneath the header …