I'm running an early 2009 Mac Pro 2.66 GHz Quad-Core Intel Xeon with 12 GB RAM, on OSX 10.8.4. I've been on Adobe Creative Cloud for over a year now. Recently, I installed the CC suite, and just the other day was able to launch and work in Premiere Pro CC.
Today, neither Premiere Pro CC nor Premiere Pro CS6 will launch. Every time I try to launch either program, I get a dialog saying "Adobe Premiere Pro CC quit unexpectedly..." (yes, CS6 even has the same dialog, saying "Premiere Pro CC" the first time I try to launch it, then just crashes completely without a dialog thereafter). I've restarted, trashed my prefs for Premiere in users/user name/Library/Preferences (I've trashed all my prefs, actually), restarted again, to no avail.
I did have an issue with being forced to uninstall and reinstall Adobe Creative Cloud, but that was before the first restart, and didn't help with Premiere repeatedly blowing up on the launchpad.
The weird thing is that I haven't installed anything since it worked the other day, nor do I have any plugins or third party apps that work with Premiere that might be interfering with its launch.