I can help its very easy, delete the game and uninstall
download a fresh version, turn off firewall and antivirus, If it still does not work try manually updating the Hack-shield by going to your Combat Arms folder. Mines is at (C:\Program Files\Nexon\Combat Arms\HShield\Update) and CLICK on autoup.exe
If it still dosent work update your drivers.
Thank me if i helped