For some reason, after driving miles along the coast in the 7th episode, I came to a long bridge with a combine fence blocking entrance to it, and the road continues away from the bridge to a tunnel, but that is blocked off also. After killing all the combines in the houses next to the bluff that the bridge is built on, I found the crossbow and a poison zombie on a path leading to a room under the bridge, inside the supports. I believe that this is the correct path to turn off the fence, because although the cable that powers the fence is visible, I can't disconnect it. However, if I try to go through the door, it displays a 'loading' message and then appears to drop me into a dark void, and then kills me and loads my last save before that. I have tried restarting HL2, restarting my computer, and just searching for an hour for a different way forward. Have I been going the wrong way, or is my HL2 bugged (and requiring a reinstall), or is my computer just incompatible with HL2 (it's worked up until now, but just in case I am playing on an HP Envy laptop, running Windows 8).
Note: Sorry that I don't have screenshots, but I am at school currently and I don't have tonight free, so Tuesday I will try to get some up. I was recording my playthrough of HL2, so while I am pretty put off by this problem, I do have video of the entire game up to this point, if it will help. (That won't be available until Tuesday or later either)