I installed Exchange 2007 in a domain which never had Exchange in it before and things went well. After things were working, I decided to reload the OS on the server to change hard drive configurations to make sure everything was installed cleanly, as there were things I had played with and had to redo. Now, I can't install Exchange off the DVD, the recover server command fails (but still installs some of the basics), and IIS on the new server is empty along with the Exchange Security groups missing in AD. Is there a way to back the changes out of AD to start this all over again? I was hoping for a clean install but I'm starting to realize that a lot of the settings are stored in AD and are all messed up now.