sir,
im installing joomla using the steps in this website "http://learn.iis.net/page.aspx/527/joomla-on-iis/" however i dont know how to do this portion...
Grant write permissions on configuration file
Joomla uses configuration file called configuration.php in order to store key configuration settings. Before running the installer you need to create this file to give the web server write privileges to the new file. Joomla's installer will modify the configuration.php file as needed with the details you provide during the installation process.
After creating the new file you can assign write permissions to it with the command (from the installation directory):
C:\inetpub\wwwroot\Joomla>icacls configuration.php /grant BUILTIN\IIS_IUSRS:(M)
Grant write permissions to tmp folder
Joomla uses the tmp folder to store temporary files. Because of that it needs to be able to write and modify files in this folder. To enable that, grant modify permissions to this folder:
C:\inetpub\wwwroot\Joomla>icacls tmp /grant BUILTIN\IIS_IUSRS:(OI)(CI)(M)