Combat Arms Help!

I had ca for a while now and i accidently deleted my engine.exe and so i replaced it out my recycle bin but it woulden't work. So i deleted all CA files, and attempted to downlad them again from the nexon website.But i download it to my downloads folder run it, it gets to the end and says 'download complete' and open or stop. I press Open and nothing happens. I really need help.

Found the problem. Thanks for help though.

do u have xp or vista?

first check ur firewall..second i dont know