Here's what to do when the Windows Explorer does not show in the Taskbar.  We've tried to reboot and maximize and minimize but no luck.  In this case one only has to press SHIFT + LEFT CLICK on the taskbar then use the keyboard arrow keys to move the window back into the viewable screen.  

The alternative is the ALT + SPACE method but the menu will show up relative to the Windows Explorer window which if off the screen.  That won't be too helpful in this case.

And we're good!

Cheers,
TK