Run Kies & the phone connected at once, I then disconnected the Galaxy Ace & connected my Samsung s2, it connected straight away. So may I suggest, for all of you having trouble connecting your Galaxy S2 to Samsung Kies download & install the Samsung Ace drivers & try again.
Galaxy S4 is not connecting to Samsung Kies. First connect your to computer through a data cable. If a message is reflected saying that USB or the device is not recognized, then the problem is related to USB drivers.
Now on your PC start Samsung Kies, then connect USB cable to your phone withoutgoing anywhere on your phone; just wait till the driver being installed on yourPC. The connection will establish between your phone and Kies.