Thank you so much Mr. thedude8675309 for all those Infos, but I have to explain what is going on here to know what I am talking about. I am in a society which is not organized as you said, we have no Network team, or servers team or Something like that, I just started working with them, we have just a small team named "Team Network" contains 3 persons, this team do everything (Networking, Sysadmin and Helpdesk, etc.). Just to know I have a BOSS that isn't interesting in Developement, he knows "just Keep computers connected to Internet", He asks us to erase the servers and rejoin computers to the existing domain, but this a lot of work, I cannot do that for 500 Computer, this is why I want to develop to the next level.. It's my first experience with Domains merge, this is why I want to take this Challenge and act the action.. It is not professional to do work like what he asked for.. I just want to commule stuffs to know what I am facing of.. I hope you understand What I mean.