fable 3

Hello, I've been having an issue where I try and play a game and i seems like it is going to load after a moment or two the process just stops. it doesn't do it to every game but the ones that do run are only through steam. some of the games that don't seem to run are fable 3, black and white 2...

I can't launch Fable 3 or Dirt 3 for some reason. It doesn't give me a error or anything when i try to launch them but it just "thinks" for a while and does nothing, but the odd thing is that Fable used to run without any problems whatsoever it just stopped working after i got about half way...