When I try to play Arma 2 and any mods for it, for example, the dayZ mod, in the bottom left hand corner I get a pop up and the servers kick me from most games because of this.
'This steam game requires a special product key, shown below. When the game asks for it, type it in as shown here.'
It then gives me a product code for Arma 2: Operation arrowhead and a product code for Arma 2: The army of the czech republic. The game never asks for these codes so I went onto my steam account onto 'games' in the top left and then 'Activate a product on steam' once entering the codes it tells me both are invalid. I have tried re-installing these games and verifying the game files and it says that one is invalid. How do I fix this problem, am I entering them in the wrong place or do I need a new product key code?