Thanks for the advice, though unfortunately it doesn't seem to be anything to do with what you tell me to work on.
I've actually fixed it with the solution listed on a thread further in this forum, where someone else had the same issue. I reinstalled my processor drivers. Now it works like a charm, though rather jerky in places but I'm pretty sure that's just the game itself.
I'd already reinstalled my video drivers and that didn't fix the problem at all, apart from making things a bit smoother. Also, my card is an 8500 GT. It has more than enough memory for PhysX, it just doesn't come with a PhysX chipset because it's an old card.
As for turning off my antivirus and firewall, I understand it could affect performance but I'm not one to want to turn them off while I'm connected to the internet. I've had bad moments when I've done that. But regardless, not only is the game fixed, it doesn't affect performance whatsoever.
So I'm enjoying the game - apart from not saving for an hour and then dying. A better autosave feature might be in order methinks.
