I was playing Portal ever since I downloaded it, and it has been a lot of fun. I tried to run it last month, but when I fired a blue portal, the game crashed. No crash report, nothing. Just Steam news in my face. I can fire orange just fine. Blue? Nope. Is there a way to fix this problem? I've tried re-verifying the game cache, and i've tried re-downloading it, and it still wont work.