HTTP Status 404 - on Eclipse with Tomcat

I am trying just to run a servlet on my local Tomcat with Eclipse.

But I keep getting this error and do not have any idea what to do differently.

I actually recorded it here : http://www.screenr.com/ZyD8

Many thanks!

Also I changed the web.xml to this:

<?xml version="1.0" encoding="UTF-8"?><web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"    xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"    id="WebApp_ID"    version="3.0"    xmlns="http://java.sun.com/xml/ns/javaee"    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"><display-name>TEST3</display-name><welcome-file-list><welcome-file>TEST3</welcome-file></welcome-file-list><servlet><servlet-name>helloServlet</servlet-name><servlet-class>HelloServlet</servlet-class></servlet><servlet-mapping><servlet-name>helloServlet</servlet-name><url-pattern>/hello</url-pattern></servlet-mapping></web-app>