I start the game and it goes through the things in the beginning. Then it has the black box in the corner that says loading... then it just closes. Sometimes it says the engine error that i need DirectX 8.0 or higher to run this game and i know i have DirectX 9.0. I tried a lot of things in the support files on the Steam website(game creators site) but it still continues to do this. At first i only had TF2 installed so i uninstalled it and installed portal but it says the same thing. Please help and thank you.