Last Year, I bought Grand Theft Auto IV on Steam (PC). After I installed it I played it for less that an hour, then I had to go out. The next day the game would not launch. The Launcher would appear, but when I press the 'Play' button, the loading cursor would appear for about 5 seconds, then disappear. No boxes would come up, and no related processes would be running. I have reinstalled the game several times since then but the same thing has happened ever since. I'm running Windows 7 64-bit.