Were you just walking around when you died? There are area triggered traps which can kill you instantly if you don't have enough hit points, but there should be a sound effect when they are tripped and the trap should be visible along with any effect. If that is the case, you can return to the area and get close to where it happened, then summon a doll and proceed, using it to trigger the trap. With the
patch installed summoning dolls can not open trapped containers, though there is a way to open such containers and avoid the trap.
In order for a trap, or powerful creature, to cause a crash, there would have to be a problem with an associated sound effect or animation, etc.
There is an in-game cutscene in the south east section of the spider forest, with an exiled spider who gives you a minor quest to kill the spider priest. If you had already killed the priest, performing the sacrifice in the north west, before talking to the exile he should not be there.
The game might be crashing on the cutscene, but that shouldn't effect the resolution. Perhaps DirectX only half switched back to the desktop resolution, or there was some problem so it (or Windows) switched to a safe resolution. On startup the game switches to 640x480 for the intro video, and then to the specified game resolution, so might have been part of it.
It sounds like the first crash may have left something in memory, which made the second crash worse.
I have no idea why Windows would reset anything in the boot menu. Was the change temporary or did you have to rename the menu option yourself? Perhaps Windows had trouble rebooting, so used a default boot menu the next time it started?
There have been similar crashes at certain locations or cutscenes, but I have never heard mention of a boot menu being reset or selection renamed.