Cd key invalid

Hello , i recently reinstalled Impulse (now gamestop) to play Sins of a Solar empire again , when i hit my games , i still see Sins on it , so it kept my old games.. I clicked reinstall , downloaded the game and when i try to launch , a stardock window comes up and asks for my cd key and email..

Okay , i go to my games , and copy paste my product key into the Stardock screen ... but it says my key is invalid , which is not possible since its already registered with Impulse? , not to mention it worked just fine a few years ago back when Stardock owned Impulse.

I already send an email to suppoer@stardock but can anyone help me?