BLANK Cloud Screen http://forums.adobe.com/message/5484303 may help
-and step by step http://forums.adobe.com/thread/1440508?tstart=0
I really appreciate the help but, i have just attempted these options and none have worked. Thank you though!
A chat session where an agent may remotely look inside your computer may help
Creative Cloud chat support (all Creative Cloud customer service issues)
Mine occasionally does this and what I do to fix it is to click-drag from the top-left to the bottom-right, which usually selects all the screen elements, including the Sign In button, and once I know where it is, I click on it, get a sign in error, which causes the screen to repaint and things show up and I can login normally.