How to change it to windowed mode?

[Joseph Stalin]

It does not have an option in the settings section.

[Tev]

I'm pretty sure the option actually exists within the game launcher's options.

http://pcgamingwiki.com/images/b/b0/Fallout_3_-_video_settings.png
See bottom left. :)

Windowed is a tickable box.

[Joseph Stalin]

Originally posted by Teutep:

I'm pretty sure the option actually exists within the game launcher's options.

Where do you mean? All of the settings (launcher, in-game, menu) were all the same to me.

[Tev]

http://pcgamingwiki.com/images/b/b0/Fallout_3_-_video_settings.png

(Despite it saying 3, it should be the same for NV.)
The pic is from the launcher's settings.

[Joseph Stalin]

Oh... in the advanced section of settings.

[Joseph Stalin]

Now, do you know if there's a way to get your mouse to be able to move outside of the window without opening the Steam overlay?

[Tev]

Alt + Tab.

(Tab is the button above the CAPS Lock -key.)

[talgaby]

No. That would be a terrible idea, you'd constantly lose focus from the game.

[Joseph Stalin]

Originally posted by talgaby:

No. That would be a terrible idea, you'd constantly lose focus from the game.

No, I mean at the pause menu. Press ESC and then be able to move the mouse out.

[talgaby]

That still would result in the same. This is an engine made for Win9x. It was never designed to be used with multiple display devices, it cannot tell the difference between being in game or at the main menu.