[SOLVED] How do I close windows?

Been using Blender on and off for about 20 years, but I’ve never known how to close windows. What I usually do is start a new project and import the objects from the other.
But this project is too big to do that, and my screen is a mess…
EDIT: I uploaded an image, mess.gif, but it is not showing.!
EDIT2: Ok, fixed that, at least; --.gif not supported.

mess|625x500

https://youtu.be/UMd-3QJefFI?list=PL0AfIdK08E7_PKsXOO_yuAql9b3hdcwPR&t=181

Start a new, file -> open, uncheck load UI option

Ah, it was so simple! Thanks!

I seem to have a new problem now; [Del] in the numpad no longer aligns view to selected objects. Even going through the menu View -> Align View -> View Selected does nothing.

Never mind, I was in polygon selection mode and had no polygons selected. What fooled me was a rectangular perimeter of edges that looked like it was highlighted. I don’t know why they looked yellow. Maybe I’m too stressed to think straight.