How do I unbrick my new Samsung Galaxy S3 i9300?

A

AC Question

Please help me unbrick my new Samsung Galaxy s3 i9300

Trying to flash Cyanogenmod onto my new i9300 Samsung (international version) with Odin, there was a driver problem (I think) and the flash aborted... now I'm stuck with a screen that says to use Kies to restore.
I've flashed CM onto several devices so I'm not a noob but this is thwarting every effort I've made to restore it.
Kies fails to connect, it just sits there on the "connecting" screen and the circle spins and spins.
Odin fails to achieve anything.
Heimdall gets almost all the way there, but then fails every time:
"Initialising connection...
Detecting device...
Claiming interface...
Setting up interface...

Initialising protocol...
Protocol initialisation successful.

Beginning session...

Some devices may take up to 2 minutes to respond.
Please be patient!

Session begun.

Downloading device's PIT file...
ERROR: Failed to send request to end PIT file transfer!
ERROR: Failed to download PIT file!
Ending session...
ERROR: Failed to send end session packet!
Releasing device interface..."

I've deleted Kies and all Samsung drivers, installed Heimdall's drivers, tried all the USB ports on my computer (no I'm not using a hub) ran everything as Administrator, turned off UAC, done every suggestion in every help forum I can find. Last option is reinstalling stock firmware, but how do I do that when none of these programs including Samsung's own Kies will talk to my phone? I can get into download mode but nothing else works.
Please help with suggestions, anyone? Thanks!