You're going to have a huge, huge problem with this. Having the game does NOT give you the corresponding server code. At all. You will have barely a hint at what communications are supposed to look like, if you decompile your game code. Even with that, you will have little idea how the server was organized, how it stored data, how it generated various events, etc, etc, etc, etc, etc.
Your best bet would be to approach NCSoft and see if you can purchase the server code and client code from them and release it as an open-source project. Once you find out how much THAT would cost, a kickstarter campaign is probably your best bet to get the funds to purchase the code. THEN there's going to be the issue of setting up a server. This will probably be a non-trivial issue as well. You will need a server with a LOT of bandwidth, or you'll need to figure out a way to repackage the server so groups of people can set up private servers.
None of this is something I would recommend to someone who describes themselves as "a newbie". I wish you luck, though, on bringing back the game you love.Go to the full post