Different ram cards generally don't work properly together. Since you have 2sets of cards you might be in a problem. If you had 3sets of two cards then you could put them each in different memory controllers and try again. Try different combinations of cards and see if any work but there is a slim chance that you won't get any BSOD at all. Any combination of cards may last but at some point in time they will end up in a BSOD.
I personally had that problem and I ended up buying a different set (all 6 card) of ram cards.
If you were able to run that config then you are extremely lucky. But as I said earlier you will end up in a crash sooner or later?
Put the corsair cards in the slots you think are non functional and try to boot it.
Generally if you have 3 cards you should put them in 2nd, 4th and 6th slots. If you pit them in the remaining it maynot work which doesnot mean that they are non functional.
If you are thinking of buying 3 more cards do it as fast as you can because if the cards are not from the same set then the same problem will repeat itself.(even you are buying another set of corsair cards and if the specs like the version number are not same you'll face the same problem although less often)