Had another go of Black Mesa earlier on, if anyone can remember, i had a problem where on the Dam level (where the first chopper appears), it kept hanging, and i had to hard restart (up to there, was absolutely perfect), anyway, soon as i started, wasn't on 20secs, just ran and opened a door, bombed, tried again, ran to the same door, opened it, was fine, so played for about 10/15 minutes or so, got to that minefield you have to get through, to get down the storm drain, bombed, so restarted, this time leaving Afterburner off, and i played for ages with no bombing, was fine.
Just played there again, for nearly 2hrs (again with Afterburner off), and it was perfectly fine again, so baffled, as i can't see it being an Afterburner problem, as it only started bombing on that Dam level, and it was perfectly fine up to there, with Afterburner running.