Why doesn't autocomplete work on MS Windows?

Question

my init.el file content:

(require 'package) ;; You might already have this line
(add-to-list 'package-archives
             '("melpa" . "https://melpa.org/packages/"))
(when (< emacs-major-version 24)
  ;; For important compatibility libraries like cl-lib
  (add-to-list 'package-archives '("gnu" . "http://elpa.gnu.org/packages/")))
(package-initialize) ;; You might already have this line

;;disable splash screen and startup message
(setq inhibit-startup-message t) 
(setq initial-scratch-message nil)

Answer 1

All your init file does is setting up Emacs so it's aware of an additional package repository. Merely installing a package is not sufficient for enabling it, you need to follow its documentation and add the corresponding code to your init file.

In this case, the README suggests to add the following (after the package-initialize line):

(ac-config-default)