Post your dxdiag. Saying that codecs aren't an issue is like saying "dust clogging my CPU and Video card won't cause it to over heat". I'll just face palm and walk away at that.
I agree. This is starting to feel like stubborness about refusing to post your DXDIAG output; it does not contain any personal information besides potentially whatever you chose to name your computer. You can just censor that part.
Granted, with this issue there's about a high probability you will not have anything in there that indicates a culprit; there is still a chance that someone will see something that could be responsible. It should be important to note though that this problem is not caused by any of the patches and had been happening with all versions including the launch version. As I said earlier though, there is a strange sort of randomness to it. Being completely unable to get through the sauna even using the "save, proceed, crash, reload, proceed, save, crash, reload..." method is unusual however so it is worth at least letting people look at your DXDIAG output and the codec lists in particular.
If you can't post it for whatever reason then there probably won't be any more help forthcoming. If it is the same sort of crash others have experienced, hopefully it will be rolled up in the upcoming (long time coming) patch. If it isn't fixed by that patch then expect to be asked for a DXDIAG output to be included in your post.
We are just trying to help here - and none of us work for Bethesda or Obsidian so we have no agenda beyond distracting ourselves at work/school/wherever.