Uninstall any previous instance of Kies/USB driver
2. Download the latest Kies, specific to your S3.
3. Download Samsung USB drivers 1.4.6.0 (I've tried newer versions but they all failed)
4. REBOOT
5. Disconnect from internet (VERY IMPORTANT!!! - forcing Windows to install local drivers ONLY)
6. With the phone disconnected, install Kies + USB drivers downloaded in steps 2,3
7. Connect the phone and let Windows install the drivers.
8. Reestablish the internet connection.
KIES:
https://www.dropbox.com/s/ay0aroxd2wdrezc/KiesSetup.exe
Samsung Drivers:
https://www.dropbox.com/s/psldnrg39p...s_v1_4_6_0.exe