Question : Trouble with moving apache website to IIS 6 and php

I have moved a website which originally was linux  to a windows server and it uses index.php as their main page. So far I keep getting a http error 404 and I cant find the reason. I also moved 3 other websites from the same linux server to the windows server without any problem (they werent using index.php as their main).
I also made use the document root knows index.php is the main page.

I have added the PHRC in the environmental variables unders system as some troubleshooting sites advised and also .php in the IIS properties > Configuration > Application Extensions. Still the same problem.

Answer : Trouble with moving apache website to IIS 6 and php

Have you added PHP extension for this website? if yes, Could you check the path is correct.
Have you modified php.ini for this website?