Renaming and Moving php.ini and php4ts.dll Files

I have PHP installed on Windows XP Pro as part of a preconfigured package (XAMPP). I'm reading a book about installing and configuring PHP which says I should rename the php.ini-dist file to php.ini and move it to the Windows directory and move the php4ts.dll file to Windows\System\ I found php4ts.dll and moved it, but when I try to rename php.ini-dist to php.ini, it says that file already exists - even though I can't see it. So I moved it to Windows\System\, THEN renamed it - but I got the same message. But I can't see php.inin in Windows\System\ either. I'm wondering if I should have left these alone since they're part of a preconfigured package and are supposed to be where I found them.