1. Check the listening port in httpd.conf, not connection if it is being used.

2. Check the path & folder where you put your file, the web files are supposed to be in "htdocs" folder.

3. Check your settings in the dreamweaver, make sure the server settings are all correct ...

4. Good luck mate~!
   

404错误一般是要访问的页面不存在，可能是路径问题。

/ajaxdemo/untitled.php

看看你的路径对不对。（绝对路径、相对路径）