So I downloaded Steam and Team Fortress 2 the other day with no problems. When I start up TF2, it goes to that black layover menu, and at the top it says 'Click here to return to the game'. Whenever I click this, the screen starts flashing and nothing else happens. If I click it a second time, the screen stops flashing. I have a 2007 macbook 13". I'm kinda fearing that the computer just isn't good enough to run the game or something like that.