Abyss Web Server is the easiest to use full-featured web server that I know of. Download Here
After installing and setting up a password, the control screen will open up in a new browser window. You can configure everything from this screen. If all you want is to run a basic website then Abyss should work will all the default settings.
The next step is to put all your web pages into the folder called htdocs and make sure your home page is named index.html. Replace the example file that is already there.
Then to access the website you can type: http://localhost into your browser. To verify that others can get to your site you could use your wan ip instead.
Lastly, forward your domain name to your ip. If possible I suggest a static ip, if not then you can use a service such as No-IP to monitor your ip for changes and automatically redirect your domain name to the correct ip each time it changes. Tutorial
