don't use it....never got it working using the installer...
open the zip folder and copy all the files to c:\php
in there open the php.ini file and read it, it will tell you how to configure the ini file to make it all go. then move the php.ini file to the c:\windows\system folder
then go into Adminstrative functions in the control panel
and highlight the webserver to configure that to read the .php extention by choosing Properties from the right click menu.
it is relatively straightforward to do...