I am not able to play this game, hardtime searcing on google doesnt help.

[I am not able to play this game, hardtime searcing on google doesnt help.]

So, I bought ArmA 2 CO from steam, to play the zombie mod Zday, some friends did it too and we installed it exactly the same. Thing is, mine doesn't work. I can't play multiplayer cause it says "Bad CD Key" and I can't reinstall the Anti cheat on ArmA 2 cause it says "This game is not avaible right now". I've tried removing the Dayz files and play it on vanilla which doesn't work either "Bad CD Key" Still I got two cd keys from each game.. did steam trick me or what?

Im using Windows "XP"

[ARMA2 & OA's Steam Thread: All Steam Q's/discussions go here [covered by Dwarden]]

Hey, just bought ArmA 2: CO from steam along with some friends. We downloaded the Zday module, and installed it correctly. Thing is, 1: I cant "reinstall" the BattleEye thing on the steam library because it says "This game is not avaible right now, try again later". When I'm trying to start and play multiplayer on Zday mod it says "Bad CD key" and I get kicked..

What am I supposed to do?

I got my cd keys as proof if anyone wonders.

btw, I cant run as administrator since I need a password for that which I dont have.

Neeeeed help.

EDIT: I run on Windows "XP".