Grey Screen with Spinning Wheel Stuck!?!?!?

Ok so I updated to Lion 10.7.3 using the combo pack, I restarted my mac and it goes through the usual chime, apple logo. But after that it goes back to the apple logo, the app logo dissapears and what is left is a spinning circle with a grey screen. I can boot into safe mode but otherwise i am stuck. I have also reset the PRAM. PLEASE HELP!!!!