tranfer magento site from subdirectory to root directory and remove the index.php from url
I am working a website where magento is used as platform. While a new site was developed all files where placed into a subfolder. suppose : http://www.mydomain/new/index.php
Now i was required to move the site form subdirectory to root directory . The client wants the url to remain only : http://www. mydomain , so beside transfering the site to root, i have to remove the index.php as well.
Problem is that i tried once to do this step and site was down for reasons that i don't know. I would appreciate if anyone would describe and guide me step by step how to do this procedure.
(PS: website is online and i need to know as well the time how long will it take and how to recover in case of problems, there are important campaigns running )