I've played FNV for over 150 hours and was meeting Mr. House for the first time. This is my second character, I lost my first character due to my computer died and he was level 40 and was happily playing through the dlcs, ignoring the main quest. But now I have a level 16 character that decided to meet Mr. House....well I wasn't all that impressed and having a good science skill I hacked a terminal, opened a secret control room, killed a couple of securitrons and decided to explore the basemant.

What I found was a shriveled old man in cryogenic suspension so I thawed him out and he went begging for his life and whined about the great things we could have accomplished. "Pathetic" I thought and shot him through the chest with my revolver, ending the quests The House always wins and The House is Bust. Now my question is have I broken the main quest? I haven't met Benny or got the chip back, this was the first time I met Mr. House.

What happens if I have broken the main quest? Have I freed the courier from his deterministic destiny? Does anyone care?

To break the MQ you'd have to kill some more people..house is just one of the important ones.

You've now doomed Vegas to a life of living under a bloated republic, a totalitarian state that will devour itself when Sallow dies or a doomed vanity project that brings anarchy with no one ruling the Vegas region. House is the better faction to support and now you've doomed Vegas. http://tvtropes.org/pmwiki/pmwiki.php/Main/NiceJobBreakingItHero.

You cannot break the main quest. There is always one option left.

One great thing about New Vegas is that you can kill whoever you want, without any of that "unconscious" nonsense, or anyone falling to one knee and never. ever. dying. no matter how much you hit them.

Of course, if you kill House, then you can't work with House (duh). There are other options for continuing the MQ, of course, but I'm sure you can figure them out.

Go pay Benny a visit, and poke around his suite.