Can't transfer files to Galaxy S3 from laptop, Kies not getting Installed on laptop

I have a Samsung Galaxy S3 on Android 4.1.1 Jelly Bean. I can't connect it to my Windows XP laptop. When I connect it with a USB cable, it's not getting mounted and thus I'm unable to transfer any files. On my laptop, Samsung Kies is not installed, hope it may be the problem. But my laptop, Kies is not getting installed, it's showing "no internet connected!!" even if I am connected to WiFi. I am totally stuck, please can anyone help?