I had the same issue on my Windows 7 (x64) machine.
1. Close CC (right mouse click on the tray icon -> Quit).
2. Go to C:\Users\[your name]\AppData\Local\Adobe\. There you will find a folder named OOBE. delete this folder (don't delete anything else in here).
3. Launch the CC, it will recreate the folder and all the required files, after a second or 2 you should be able to see the screen asking for your login and password.