Huh, That's Strange! (Disappearing Window Manager in Ubuntu)

I've been a casual Linux user since grad school. By "casual," I mean that I have installed various distributions (Vector Linux, Mandrake (now Mandriva), Puppy Linux, Ubuntu) on my home computer/laptop over the years, usually to try to squeeze another couple of years of life from an aging system. Other than some obligatory mucking around to get things installed initially (which is increasingly rare for mainstream distributions), I don't do anything that might be considered Linux administration.

In the past, when things have gone wrong, Google usually provided the answer. In fact, many times the bigger problem is finding a working computer on which to do the Googling in the first place (which can feel like an inherent contradiction:  "Internet not working? Visit our website for details on how to troubleshoot common connection problems").

I'm currently running Ubuntu 16.04 LTS on a laptop at home. For the most part, I've had no problems (other than those that I've created myself) -- things have "just worked." 

However, two (or three? I've lost count) weeks ago, I booted up the computer only to find that the task bar had disappeared. I was staring at a blank screen, with just the default background. (Huh, that's strange.) The mouse pointer was still visible, but there was nothing to click on. 

I could still right click to bring up a terminal and start programs that way, but any application that started did not have window management. In other words, there was no way to drag, resize, or minimize any window. 

Over the next couple evenings, I tried a number of suggested fixes, but none seemed to work. Yesterday, I finally came across the magic commands that worked for me (from this post https://itsfoss.com/how-to-fix-no-unity-no-launcher-no-dash-in-ubuntu-12-10-quick-tip/):

sudo apt-get update
sudo apt-get install –reinstall ubuntu-desktop
sudo apt-get install unity
rm -rf ~/.cache/compizconfig-1
sudo shutdown -r now

This may be moot soon as Ubuntu 18.04 LTS should be out any day now, but I thought I'd share.