php 5.2.1 and php.ini problems on Win2003

Hello all: I'm having a problem running PHP files (the browser shows a blank screen only), but only if I left my php.ini file in the c:\windows dir. If I remove the php.ini file, it runs correctly. I also could not make the system look fo the php.ini in the C:\PHP dir, even settting the PHPRC enviroment variable. The problem is that I need to set the extension_dir variable to C:\PHP\EXT, but I'm unable to do it, because it does not read my php.ini. I have other servers running older versions of PHP (5.0.3) with no problems. Thansk for your time. -- Jackson Gomes