Similar problem yesterday with my Galaxy S3 and new Windows 8 system. I installed Kies and the USB driver offered at the same time. The phone was not recognised despite going through the error identification routine a couple of time. Is it just a coincidence that shortly afterwards (after I had disconnected my phone from the computer), I received a firmware update to my handset from Samsung ? Paranoia beginning to set in!
As an aside I also had no joy a while back when trying to make it work with my old Windows XP system.
Would appreciate any update.