So I went away, letting Mail load messages as this was an initial install of 10.10.3 When I came back my old nemesis, won't wake from sleep, had returned. Thought Yosemite would have fixed the Power States issue but apparently not. Hard restarted it and now, after the Chimera screen, it goes to black and then restarts, an endless slow cycle. Did Verbose and it stopped briefly before entering the black screen and restarting: