I have just purchased the game but it is not working on my computer. When I try to run the game, it just stops loading and afterwards nothing happens. I have tried to do copying down the serial key from GOG to steam but the key I have got is invalid on Steam. I don't know what to do. Can you guys help me ? Thanks

GOG dont provide steam redeemable games.

Did you install by running as admin in the default install path?
Did you run the game as admin?

Is your firewall or antivirus blocking the game from launching?

You can also try to add the game to the list of DEP exceptions (you'll have to google thar, sorry - posting from a smartphone with a low IQ).

I'm all good now. I've contacted GOG support about the problem. They've been very helpful to me. So no problem. Thanks for the reply.