Make sure your antivirus is off and that when you press insert don't select chams, select for now wallhack only. The more you play then you could start adding crosshair, fullbright etc etc.. hope i helped
Also in login screen press insert, after you've selected wallhack press insert again and make sure the mini box on the top left hand corner goes away then you can play. DON'T LEAVE THE MINI BOX OPEN---AND DON'T PRESS INSERT AGAIN AFTER YOU'VE CLOSED IT WOULD FREEZE CA AND IT SUCKS!