I am wanting to beat the whole fallout: new vegas game by doing all the quests and exploring all the places. I wanted to do the "The White Wash" quest but i can't trigger it becuse when I tried talking to Boyd to trigger the quest, she will be talking bad about me because I killed Silus to get one trust point with Boone. Is there a way around this or I simply won't be able to do the quest?

Not sure, I wasn't able to get the quest untill I asked about the missing people and then asked if there was anyone else. Then again, I've only had boone as a companion when I just start out so, I can't really comment on that part, but I hope the first part of my reply helps you get the quest.

I know that we need to talk to her about this. The problem is that she don't want to talk with me because I have killed Silus. She got angry (not hostile) with me but I am still idolized by the NCR. When I try to talk with her, she says something like this: "I hope you are happy with what you have done". The only option I have to answer is "Goodbye". Does this means that i won't be able to begin the quest?