I actually found the answer to this problem pretty quickly.
The php installation software did not work for some reason on Windows Vista. The only thing I saw that the installation program did incorrectly was that it id not add index.php as a directory index.
Therefore simply changing this: DirectoryIndex index.html
To this: DirectoryIndex index.html index.php
fixed the problem.
I also copied php.ini to Windows folder for good measure. Why? Because someone said to do that in a forum. I figured it couldn't hurt anything, not being an executable to begin with.