You might try going into your game folder and deleting clientregistry.blog . I had a similar problem with CSS at one point and that was my fix. Additionally, try entering this in your launch options for the game (right click on game>properties>launch options) -dxlevel 80. this will lower the software level your game uses and can fix some graphics issues that might be causing a system hang. Be mindful, these are only fixes I have used for CSS problems. But its all source, so give it a try. Let me know if it works or not and Ill try to help with some more troubleshooting