The list is long...
Do the boot-up messages appear when it's starting, or is it in "hibernate" mode?
If it's hibernating, it may need some brute force to persuade it to see things your way. I don't use Win 8 (went swiftly back to Win 7), but try the "shock safe mode" - when it's sitting there showing you a mouse pointer and nothing else, pull the power plug out of the mains (don't tell it to close down).
That will make it very cross when it restarts, but with luck it will offer to start in "safe mode".
If it does the normal startup, press F8 many times while it's doing the first part, and it should offer to start in "safe mode".
Do the "Safe mode with minimal set of drivers" thing, whatever it calls that, and see if it works or if it tells you what's wrong.
If you get to a sensible desktop screen, open the control panel, go to "Administrative Tools" then "Event Viewer" then "Custom Views" and "Administrative Events" and see if there is anything there to indicate what's wrong.
If you did the "pull the mains plug" there will be a message about an unexpected shutdown - that's normal.
The error messages will give some idea of what might be wrong.