You could try opening task manager then ending explorer.exe this should wipe the desktop,then in task manager click file new task(run)in the box that opens type explorer.exe and click ok this should restart everthing and maybe get your taskbar back. If it doesnt then restarting the pc will just put things back as they were.
"In the Computer Management (Local) list, expand Local Users and Groups."
This is missing from Computer Management and I can't get into New User from the Control Panel. I can click the User Accounts link in the Control Panel but when the screen pops up all that shows is the two icons for 'back' and 'home'
I tried the fix but no joy.
I'll go and have a look at the 1st link you posted.
Have you tried putting the cursor right to the bottom of the screen until the double arrow appears? If you move them upwards it may be just hidden and come back and then you can see if the settings have been changed by right-clicking on open space in Taskbar.