Just when I was getting somewhere...

I think I've got a damaged save game. Three seconds after coming out of town, I get a Windows ping and the game freezes. If I then press any key it crashes back to the Windows desktop.

What I want to know is:

1) (Medium importance) Is there any way of fixing it? Because if not, I'll start the game again rather than going to an older save (I missed quite a lot of stuff).

2) (High importance) What caused it? I don't want to fight my way back to Anephas's shrine all over again just to have the same thing happen. Can I avoid it? And if so, how?

Thanks in advance for any thoughts you may have...