I have played for several days now and hadn't even gone in to New Vegas. When i finally got around to doing so victor approacher me and asks me to go see Mr House. so as I walk up the steps of the 38 there is victors body on the steps as the victor i talked to is escorting me into the building. I go into the casino and all the robots including victor start attacking me. I killed them and went up stairs and then those robots attacked. Hr house also has no dialog for me as well. I am wondering if anyone else has had this issue and if maybe i did something in my previous travels to make this happen. Perhaps I should have gone directly there but i was under the impression that I could wander and do the missions as i please.

Spoiler alert

Also i had an issue in the hidden valley BOS base when you have to help get rid of the virus in the database. If i used my science skill to fix the computers it would not let me retry the task. Only if i did it with out the skill didn't it let me finish the task.

I have 36 hrs invested in this game and i would hate to have to start all the way over, especially not knowing what i did to trigger the robot assassination.

I don't know about the first part, but for the virus mission you DONT use the science skill, I forgot exactly why but apparently it breaks the quest.

I'm having the same issue as the OP. Got a message saying I had failed the quest "The House Always Wins" while exploring in vault 11, possibly related? If so is there a possibility of resetting it or do I need to reload from before vault 11 and loose several hours of progress.