Simple servlet not started

Hi,
I have Tomcat 5.0.25.
I can start a jsp but not a simple servlet. I have the servlet compiled class and java class in the default directory ...C:\Tomcat 5.0\webapps\ROOT\WEB-INF\classes. When I call:
http://localhost:8080/servlet/HelloServlet
I got the error message HTTP Status 404: "The requested resource is not available".

I have the variablen JAVA_HOME =C:\j2sdk1.4.2_04,
CATALINA_HOME=C:\Tomcat 5.0
and the PATH%JAVA_HOME%\bin;%CATALINA_HOME%;C:\Tomcat 5.0\common\lib\servlet-api.jar

What can be wrong?
I hope somebody can help me.
Regards,
Maria

1. You are using a URL that requires the "Invoker" servlet - this is not a good idea, see this Javaranch FAQ on the invoker.
2. I bet you didn't put the servlet in a package. Tch.
3. This is THE MOST COMMON problem mentioned in this forum - browse around in the recent posts to see more discussion.
Bill

Many thanks, William. Now it is working.
Your answer was a great help for me, I have tried so many times by changing something but nothing was Ok.

Regards,
Maria