well I'm not exactly sure what happened here. I'm stuck at the part where I am at Boulder City and just finished Boulder City Showdown. I forgot what happened, as I went to do other quests and when i came back to do it all the NPC's were dead. I sided with the NCR and went in guns blazing and killed all the khans with the help of the NCR troops, I come back to the place to find that there are no more NCR troops left, and the quest marker tells me to go inside the hideout (the door all the way to the right that is a 1-room house) I remember going in there and killing all the khans in there, but now going back,there are no corpses at all, and when i go inside the hideout the quest marker disappears. There are no NCR or khan NPC's and no corpses. The only NCR NPC's left are the ones outside of boulder city standing there but you cant talk to them and all they say is thank you for helpin out. How do i fix this, as this is a main quest and i won't be able to continue the game without completing this. I saw some video of where you have to talk to the lieutenant of the NCR if you side with them, but he is nowhere to be found. What can I do without having to restart the game because I am already 30+ hours in.

Thanks a lot for taking the time to read this and ANY help is greatly appreciated. If anyone has this please post here as well, because I have not found anyone having this problem.

bump. anyone?

this can be done through the console, only problem is, i dont have GECK installed and the base id for the quest is not on the wiki, if you or someone you know do have GECK installed look for the quest, it also shows all the stages

from what ive read in your post, my guess is that your stuck at the last stage named "Intercept the Great Khans at Boulder City.", correct? if so, once you have the base id for the quest and the number of the stage you're on (stages are numbered for example: 10 20 40 60 80 etc..) from the GECK, use this console command:

setstage "base id" "stage" (without the " )

if done correctly, the quest will complete, again, i dont have the GECK so i can not find this info for you, try asking on the fnv wiki forums or teh GECK section here to look it up if you dont want to install it either

ok let me get this straight you got the quest Boulder City Showdown, then you left and did other quest or went in guns blazing then left to do other quests? Also did you even loot the Khans or go inside and look around? you don't give enough details or rather the chronology of what you said you did doesn't make sense.