Episode 1 keeps crashing

[Diputs]

I was playing Episode 1, and it was going fine for a while. Anyway, after the Grav. gun gets supercharged, I go down a hall, turn, and the game starts loading. It makes it through the loading and autosaves, and I can see down a hall, with combine running across a bridge above, and a suit charger forward and to the left. Anyway, if I go down the hall looking in that direction, the game stops, and crashes. However, if I go down the hall looking back (at where I came from), then I can go, but if I turn around, it stops and crashes. Also, I can look that direction fine as long as I'm at the back of the hall, but if I got too far down the hall, it crashes.

I have no idea what could be causing this, and my video drivers are updated. I tried running it without any sound, and in a window, but it doesnt help.

My system specs are in my sig, but they should be fine, and I was able to run HL:2 perfectly, with all high settings.

Any ideas? Thanks for your time.