Hi shiva
Maybe you try http://php.weblogs.com/easywindows, a PHP-Installer for Windows.
If you install Apache, take care to set proper paths and extensions in httpd.conf.
Maybe you've only registered .php as extension, so Apache won't recognize .php3 files...
With the following line of code (one one line) in httpd.conf you'll register .phtml, .php, .php3 and .php4:
AddType application/x-httpd-php4 .php .phtml .php3 .php4
Hope it helps
Christoph