Few problems downloading :)

[Seano_poker 0]

Hi, first of all sorry if this is somthing obvious, im terrible with computer stuff, just like playing the games :)

My first problem is with both Arma 2 and Arma 2 OA. The problem is when i go to play them (through steam) i click it and all i get is the screen flash up black, then takes me straight back to desktop. I can hear music and the game is on the task bar, but when i go to click it, it just flashes up black for a split second, and diverts me back to desktop. But for some reason it works in windowed mode, which is annoying.

My second problem: Arma 2 isnt the game i wish to play, i wanna play dayz. So i downloaded to files and put em in the correct places after following a youtube vid. Then opened the game in windowed mode (no choice otherwise it wont load) and a messege pops up, CA Building Blocks Missing, i have no idea what this is so i clicked continue in a hope that it was nothing, then the menu screen pops up for the game, and it says im missing some FILE, so i click continue in another hope that it will no affect dayz.

I go to server list and filter dayz and click to join and it says i either have a bad version or not god enough connection.

Just to note it cant be my computer specs as they are top of the range said the man in shop when i bought it 1 month ago.

Anyhelp would be great , Cheers guys :)