why i can't execute my php codes

I have a problem! I cant make work PHP with Apache . php is : php 4.2.1 apache is : Apache Server version 1.3.23 the installation is successful , but when i'm tring to run the php code i'm not able to see any thing in the browser except the title in the php code "Hello World". I made the php code in dreamweaver 4 and saved it in the C:\Program Files\Apache Group\Apache\htdocs and when i tried to execute the code in the browser by giving http://192.168.0.170/php_test.php i'm not able to see any thing in the browser except the title. I also want to know that every thime i have to execute a php code i've to save it in the C:\Program Files\Apache Group\Apache\htdocs, if yes the nis ther any way out that i can execute my php code saved in any folder and any drive on my hard disk with out saving it to C:\Program Files\Apache Group\Apache\htdocs. and wht abot those information which i provided during the installation of apache server info like : Network Domain : Kuwaitnet Server Name : Murtaza Administrator's email add : m_chandan@kuawaitnet.net wht r these information, pls help , regarding this. best regards murtaza