Can Spotlight be configured to search ALL files on the hard drive (or is there a powerful alternative) - like Windows' Start Menu search can be? On Windows - since Vista onwards - I'm used to an extremely powerfully configurable instant file/folder/setting search feature: namely its instant indexed Start Menu search. Having a powerful computer, I add every single file and folder to the index so that any little file or folder I'm after (including both file name and extension), is immediately, instantly searchable right from the Start Menu.

It looks like Spotlight is OS X's equivalent of this.

Is there a way I can achieve the same thing, to index every single file on the hard drive, in OS X? So far I see no in-built way to add custom/system folders (or indeed all folders) on the Mac outside the ones it offers, like on this screenshot:



If there's no in-built solution such as a set of Terminal instructions, is there a good third party solution for this? (As always, free options are more desirable than paid.)
I can recommend EasyFind and Find Any File (of which I'm the author, incidentally). Both search for file names on entire disks.

They search even in places where Spotlight never looks (e.g. in the System and Library folders).

In case of Find Any File, you can even easily search as root user, so that it even finds files usually not accessible to you. FAF also lets you save a set of preferred paths, either as a default or as a "search" document that you can open as a pre-configured search configuration.