Hi mrcead, it seems to me from your problem solving that the windows installation on the hdd has become corrupted.
When you start in safe mode, un-install the display drivers and then re-start and see if windows will log onto desktop.
At this point it should say found new hardware and try to install the default windows driver for your graphics card.
If not, you will have to re-install windows on this hdd, happens sometimes :-(
Good luck and keep us updated on how you get on.