Here are my circumstances:
1) Load Dead Money
2) Received radio signal and mission
3) Walk to Abandoned BoS Bunker
4) Enter the bunker, crash during loading screen( Besides that, game also crash when I enter Silver Rush )
5) Give up Dead Money for that moment and continue the game from that point( DLC mission and marker remained, and I did not unchecked Dead Money )
6) I realized my leveling stop when I reached level 30
7) I save my game, then unchecked Dead Money
8) After that I load my game, and i found something weird which is I still can see my Dead Money mission and marker even i have unchecked Dead Money.
9) I save my game again, checked the Dead Money and load my game
10) I go back to Abandoned BoS Bunker, found that it is locked
11) I use resetquest command to reset mission. I save my game and hope I can get the mission again.
12) When I load my game, nothing happens

Can anyone please help me?

get fnv edit mod and run it, check in with the mod thread for the mod.
run it, left click on left side of screen and select apply filter
then see that only the following is checked off:
by conflict status overall
conflict
critical conflict
conflict status inherited by parent
now click on filter in the lower right corner
this will show any mod conflicts

make sure u go to the bunker alone. people have had crashing when they followers with them.
check other threads on this and how they solved this.
i would also load an old save from before u entered the bunker.