Blank screen after Norton update & reboot

Have an HP laptop running Norton 360.  Got an update the other day which required a reboot.  After the reboot the task bar was not visible.  I tried to see what was wrong, not the desktop is completely blank, nothing showing at all.  Looking thru the disk for startup files I can start up applications like MS Word, Edge etc.  But the Windows UI seems gone.  What to do?  Grateful for any help.

Have you then done a reboot see if all is ok?. I have an old laptop on Windows 8.1. Something used to happen, if on the same day, another app had self updated unknown to your self,  could not even get to to completion of log-in or it would take a long time. A forced shut down, then a reboot would boot normally with installed programmes showing that app had installed & updated, could then proceed with full install of Norton by running LUD. Now, I do a restart prior to running NIS update ensuring the other app was fully installed. May perhaps be something similar?

Sometimes, when cold booting, desktop appears, no screen icons, just one or two in taskbar, finally after a minute or two, all will appear, then find, during boot, Google Earth or some other app had self updated during boot process.