And i am back with SE response. I must say they were fast and i was pleased with their answer hehe.
So here is what i asked : "I have a copy of final fantasy XIV that i got a while back but due to some events i didn't have the time to register the game nor even install it.Now that i can i saw that you are re launching the game.Can i still use the copy of final fantasy xiv (with the unused code) i had bought back then and play the new ff xiv. Thank you for your time."
and this is the answer i got from them : "Dear ***,
Thank you for contacting the Square Enix Support Centre.
We are very sorry that you are unable to register for Final Fantasy XIV.
Since November 11th, 2012, all worlds of Final Fantasy XIV are offline and active service accounts as well as registrations are suspended until the redesign "Final Fantasy XIV: A Realm Reborn" is released. You will then be able to register the code you already purchased. Unfortunately, we do not have any information on the exact time of the release at this time.
At the moment, the beta phase for A Realm Reborn is underway. If you wish to participate, you can apply for a Beta code here: http://entry.ffxiv.com/beta/eu
We apologise for the inconvenience.
The Square Enix Support Centre team"
With that we now know that any unused or w/e code from 1.0 we have we can use it to play the new a realm reborn.Something that i believe as i already said is right since i/we bought the game. With that response (and a fast one as well) i must say that SE gain a few points in my eyes!
Hope this helps the rest of the people to easy their minds.