Do you get:
Spinner spins for the usual amount of time
screen goes blue or black at the point where you would normally login?
That is exactly when the graphics card is shifted to automatic. Although that also is the point when added kernel extensions have been loaded and are made active, users report this symptom often correlates with graphics card failure.
Safe Mode does not use the driver or automatic mode, so being able to operate in Safe Mode adds credence to graphics card failure.