1.Ok So Start Regedit

2.Then Go To HKEY_LOCAL_MACHINE , Software , Wow6432node , Bohemia Interactive Studio (MAKE SURE IT HAS THE STUDIO AT THE END OTHERWISE YOU WILL FULLY DELETE YOUR GAMES AND HAVE TOO PAY FOR THEM AGAIN!), Then Delete Folders Arma 2 (If have) and Arma 2 OA.

3.Load Up Steam In Admin then Right click Arma 2 OA , Properties , Local Files , Verify Interigty of game cache... Then wait till done , you will need to do this with Arma 2 if you have it!

4.Load Up Both Arma 2 and Arma 2 OA or Arma 2 OA (if you have no Arma 2) in windowed then exit both on menu!

5.Then You Should Be Good To Go.!

Regedit Help: ---> 6b8a0510661854ed5bc84ac5522fc404.png