Give this a try: Boot into safe mode, but Select option "enable Boot Logging
Have seen instances where your problem was caused by several different reasons, EG, keyboard key stuck, a bad device driver, even a bad update from MS live (although that one was some time ago) and probably not relevant.
Other users, just let it sit there & walked away, and at some point later 1/2 hr or longer, it booted.
You might want to read thru this post for more info: Toms Hardware
Provided you have a Windows Install CD, I think a repair is in order.
Edited by USN Vet, 20 July 2011 - 02:59 AM.