Updating to High Sierra- frozen
I tried to update my MacBook to macOS High Sierra & it gets to about 37 minutes & won't go any further. It says there is an error & to restart to begin diagnostics. I have done that & no problems. I have tried to reinstall- can't. I have tried to force quit with the control/ command/ escape keys & nothing happens. I have no menu bar at the top. I can't tell any of the operating system or any relevant specs as I can't get to them.
Any help on how to stop/delete/quit this download would be most appreciated.
thanks
MacBook