Configuring windows 2008 server

I already have a windows 2008 server which I use for hosting services. I am able to host websites (design them & upload via a FTP software). But when my clients use drupal, joomla other softwares to upload, create directories they are not able to do so. Only possible way is to use FTP software. I need someone who can do all the necessary configurations in ASP, PHP, etc & all other configurations required to run the modern scripts without any problem. If anything is left out please add it to list & make the server work good. If anyone is employed to work on this project. I would like to make a note that there are existing websites on the server & I would not like them to be disturbed, as it will effect my clients.