Localhost allows you to access web servers running on your own computer using http://localhost or 127.0.0.1. It is commonly used by developers working with tools like XAMPP, Apache, Nginx, IIS, or other local server environments. If localhost is not working on your Windows system, this guide covers the most common causes and fixes - from a simple hosts file adjustment to port conflicts, proxy settings, and Windows Update regressions.
Quick answer: Start your local server, open a browser, and go to http://localhost. If it fails, the most common fix is opening C:\Windows\System32\drivers\etc\hosts as Administrator, commenting out ::1 localhost, and ensuring 127.0.0.1 localhost is present and uncommented. Save the file, restart your server, and try again.