The correct one to start Tomcat is startup.bat. But don't double-click it; open a Concole window, change to the Tomcat directory, and then type "bin\startup.bat". That way you will see if there are any error messages.
I appreciate your reply but you may misunderstood my question. bin/startup.bat is ok. My question is I want to reset the environment variables by double click bin\catalina.bat and bin\setclasspath.bat. But they are not working. I just saw a window jumps out then closes quickly. The environment variables are not set automatially.