Probably need some more info.
So you are installing PHP and MySQL and Apache ONE BY ONE on Windows?
If you want Apache and PHP and MySQL, I suggest you take a peak at http://www.en.wampserver.com/
A single installer that does it all. But if you really want to do the grunt work yourself. I can understand.
I suppose the simplest question is to make sure you have restarted all the services after editing php.ini and so forth. To make the settings stick.
Then make sure you type "locahost" or "127.0.0.1" into the browser when you type a URL. Once you think everything is set up right, and you placed phpinfo.php in the web folder as defined in php.ini, and php.ini is in the correct folder. Then type:
And that should work.
Keep it up though!