Can't transfer files to galaxy S3 from laptop?Kies not getting Installed in lap?
Select the 'Mass Storage Only' option in the USB settings and then connect the cable.

If this doesn't work, you can connect your laptop and your phone to the same wireless network and use AirDroid to transfer files wirelessly from your laptop to your phone and vice versa using a browser on your laptop. Both devices just have to be connected to the same wireless network (with or without internet access).

Hope this helps!