Windows 11 upgrade disaster -- taskbar, settings & start menu gone

I hope someone can help with this.  I have an Alienware Aurora (about a year old).  I was running Windows 10 and got the prompts to upgrade, so I downloaded the upgrade and I set it to install this morning.  I have come back to my computer and the taskbar is gone entirely ---- it is just a long black bar along the bottom of the screen.   The only feature is the up-arrow to show items in the system tray.  I cannot open (with mouse clicks or keyboard shortcuts) the start menu or the settings menu.  I can get to the control panel using the run command.  What do I do to restore this?  I tried running SupportAssist OS Recovery, but it didn't do anything.  I can't open the Settings so I cannot get to the Recovery submenu option, and I don't see anything similar in control panel.  Any ideas?