Thought I should mention this in case similar has caused problems for anyone else.
I recently had a Black Screen at start-up. I spent three days in Safe Mode trying to sort that before clutching at the straw that had caused the problem. In Safe Mode I could see no problems with drivers, nor with anything else.
I had shut down the PC with an HP P1000 inkjet printer still running, and I had switched the printer off before switching the PC back on. (In the past as any printing I had done had not been at the end of my use of the PC, I had switched the printer off long before I switched off the PC).
When I tried switching the printer on again before starting the PC it started as normal.
Surely this should not happen - does anyone know if this is a common problem and if so why does Microsoft not tell us about it? If you look for Black Screen on the Microsoft site they say it could be because you have left a non-system floppy or CD DVD in a drive. Otherwise they say it is because of a fault master boot record.