Fozzie

I used to be an IT manager in both military and civilian environments in the days of NT4 and we used to experience 'Blue Screens of death'  which I suppose is the same as you are experiencing with Windows 8.  I found out that one of the causes of this was memory - what was happening is that overtime the computer writes processes to the memory and then when its done with them allows that memory to be used for another application but in the cases that I came across when working for a software development company was that the application was not releasing the memory to be used again so eventually it would run out of memory and give the 'Blue Screen of Death'.  This could be what is happening to you as its taking over an hour to crash and it crashes when looking for a relative small amount of memory.  As you have tried most other things could this be the cause of your problem?