I was trying to enable an extension (xml-rpc) on iis6 with php, but i didnt want to restart iis. The steps is to

1. create a php file in your root folder or subfolder with a php code “phpinfo();”
2. navigate to that page and search for the extension you want.
3. locate the php.ini file on your server (check the phpinfo to get hints on where this is)
4. now enable the extension by removing the semi colon.
5. go to iis6 manager on your server
6. right click on default application pool
7. and select recycle.
8. check your phpinfo file again and the extension should be loaded

good luck