It was sealed. And if it was used,the serial could've been scratched already. There's no way my friend could ever replace it again because he bought this a long time ago,just didn't have time to play it.
Oh LOL I misread what you wrote. Sorry.
Umm how old is it? Over my GW serial key it says if the key is messed with in anyway that it is considered void.
So you will have to get new key some how. Good luck.