I commented on your problem to a tech person, who said he suspected a hardware issue: a defective card or connection. His logic was that windows has a default low-level routine for talking to any video card in safe mode. If that is not working, the card is very suspect.
Carrara, with its card-heavy user interface could have walked right into the problem, but only by coincidence.
Sorry you are having all this trouble! I would be chewing my keyboard by now, if this happened to me! :)