I have tried 3 different repacks of Portal over the last few days, just to try and get it working, each time fail.
I've also reinstalled Windows 7 about 3 times now, but nothing stops Portal crashing.
My latest attempt is to try reformatting my ENTIRE hard drive just before reinstalling Win 7 AGAIN!! surely that should do the trick??
Actually this situation has been driving me crazy these days, and wasting no end of time. I know it's crazy.
You see I'd actually been playing the game for nearly a week before all this started, I'd very nearly completed it, so I know my system can run it. I totally do not get why it keeps crashing now.