please advise

Hi There I am totally new to PHP and have just tried installing it on my machine according to instructions on the php.net manual installation instructions page - http://www.php.net/manual/en/install.windows.manual.php I think I managed to do most steps but I have a few questions: Under the PHP file, I have icons for php, php-win and php-cgi. If I double click on any one of them, it says - "Are you sure you want to run this software?" I have Windows Vista - 32 bit operating system and have installed IIS7. Which one would you recommend that I run? Then, how do I know that everything is installed properly? Under optional steps: How do I change the doc_root to point to the web servers document_root?? This was an optional step but not sure how to do this? (sorry basic question!) and what extensions would you recommend that I install? I look forward to any advice! Many Thanks Louise (South Africa)