If you think you already follow the procedures to install apache, php and mysql, but still cannot get the desired display using browser, then there might be another place you have to check -- 'ServerName' in the httpd.conf
I guess you're trying PHP at your localhost, just add/edit
ServerName 127.0.0.1
into httpd.conf
and type
http://127.0.0.1/yourphptest.php on the browser.
Hope the suggestion can solve your problem.