What.Game.
Was it a certain anti-virus, or was it something that you've never heard of and popped up randomly? Because alot of viruses actually make it look like it found viruses, and when you "Scan and remove them" it just installs more viruses.:O!
The malware didn't come from the game.It was likely dormant in your PC so you wouldn't know where it came from.
Steambirds is a game you do not have to buy or download and that's the first smart thing in this thread, but what is a Trojan?