Power, i understand were you are coming from.
It happened to me
I got to the part were you are at a big bridge and you have to jump across all the steel girders (trying not to spoil it.) Then i had to re-install windows.
After that i completed the game. Then i completed again before i played Ep 1 to refresh my memory
It is a very long game, so it is understandable that some people don't get the opportunity to complete it for various reasons.
Could someone link me to this mod please? I have never been a big lover of mod packs. But if it improves textures i am all for it!