Reporting back with some news, I reinstalled windows and still got a crash, this time with a ntdll error. That prompted me (after some frantic google searching) to run a windows memory diagnostic scan which did find errors with my ram. I would get occasional bluescreens that I now know were related ...

I've experienced this crash on 1.1.35 and 1.1.36 on both singleplayer unmodded, and multiplayer with biggerbags 1.0.35 and bottleneck 0.11.7 installed and enabled. I first checked out the common tips and updated my bios (m5a99x evo 2.0 version 2201 to 2501 (current)) , which seemed to work at first ...