Ouch! How is that even possible?
As I understand everytime you have sent in your notebook is because of MB failure, but now with extra information, it sounds like they don't know what they're doing :S
You could pm @MarshallR and ask him what to do. Ofcourse the best would be to get a new notebook, but then you never know if you get a new issue that you haven't dealt with before.
Asus G73SW-91058V 3D
- Intel Centrino Ultimate-N 6300
- BIOS 205