How do I restore the original window configuration? I have made a real mess of things. Each time I try to close one "viewport" or whatever they are called, another one is created, and now my entire screen is a MESS. I just want the original window configuration back, with Tools, Outline, and main window. Right now, I can't even access User Prefs, to see if that's how to do it because there's some kind of "wrench" over it, and it cannot be opened. Help?
In 'User Preferences' under the 'File' tab, you can uncheck the 'Load UI' option.

Save User Preferences.

Then restart Blender.

This will cause blender to load the default window layout.

If you want to keep a window layout, you need to remember to re-check 'Load UI' once blender has restarted.



To close individual panel, you can drag the corner with the arrow of neighboring panel with the same height or width. This is using the outliner to close the properties panel.



The link posted by @poor has this answer, you just have to wait until the end of a 30 second gif to see it in action.  (is there a TL;DW for gifs?)