My Apache server is stopped
 

I Install CentOS5.2 and configure it as Apache webserver. It was running well. but today I install Tomcat5 after I have restart the tomcat5 service my Apache server stop to responds. How I can make working both.

You don't say anything about what you're trying to do, so it's hard to say. My guess would be that tomcat is running on port 80, and apache is also. Configure one of them to use a different port.

I agree, stop tomcat and try starting apache, if it starts then port 80 is definitely the problem, either configure apache or tomcat to use a different port 81 or something... apache should give you an error on screen when you try to start it, if it doesnt you could always check your logs usually in /var/logs