yeah,i am running php on WINXP and IIS and i've got the same problem as u too , knizam but mine i found my php.ini file but the content of the file is different from the original php.ini.
Configuration File (php.ini) Path C:\WINDOWS\php.ini
when i xcess the file, this are the contents.
; php.ini for PEAR tests
include_path=..
[mail function]
SMTP= localhost ; for Win32 only
sendmail_from= me@localhost.com ; for Win32 only
upload_tmp_dir = d:\PHP\uploadtemp ; temporary directory for HTTP uploaded files (will use system default if not specified)
[Session]
session.save_path= d:\PHP\sessiondata ; argument passed to save_handler
error_reporting= E_ALL; display all errors, warnings and notices
so where did the original php.ini is located??i did try the method from Duncan but still have the same problem