CS6 is not required. (Though you will need to install CS6 to get Encore, as there is no CC version for that.)
Type Crash on Launch into the forum search. You'll get plenty of hits and some ideas.
Do not uninstall CS6
OK, so I won't be uninstalling CS6 any time soon! But I'd still like to have some feedback as to why CC won't launch. I got the impression that CC had some neat new features, but if the program doesn't work, how good are they? Based on what I'm reading on the forum, CC ain't quite the "greatest thing since night baseball." Plus, I'm not unhappy with CS6. So until CC is fully de-bugged and will be more dependable--which it isn't, since it won't even launch--I'll stick with CS6.