I have home windows hosting and I have created a php web application, when I am hosting my application under root directory (web) creating new directory. After i attempt to access the index.php, it provides me with error "bad server request" bla bla bla.

Please let me know how you can fix this issue?

First see if the PHP is correctly installed just upload a webpage with this particular coding and find out if u obtain a response <?php phpinfo() ?>

if no response..

Please speak to your hosing provider . Home windows servers does not support php extensions you have to switch to a linux server or perhaps a upgrade

could it be running inside your local machine you are able to install php extensions using Microsoft web platform installer

The Microsoft Web Platform Installer 3.