First thanks for the replies and I take onboard the warnings about BIOS flashing although I am well aware of the potential dangers. I have been building my systems since 386 days going back to Win3 and have only once flashed the BIOS. In fact, the reason for posting my question is specifically because I am concerned about the flash failing but it appears to be the last resort to try to resolve my problem and even if successful there is no guarantee that this will solve the problem.
I have been asking for help from the MSI, Gigabyte and NVidia forums having exhausted everything I could think of trying - the MSI forum was where it was suggested I flash the VBIOS. Gigabyte technical support has told me to flash the BIOS and that is where my question comes from and my reluctance to flash it. There are 3 ways to flash my BIOS: an inbuilt tool (QFlash) built into the BIOS, a Gigabyte utility (@BIOS) that can be run from Windows and an executable that comes with the new BIOS file that has to be run in MS-DOS.
I cannot use QFlash as the latest BIOS is a 2MB file and my current BIOS QFlash will support 1MB BIOS files only - the BIOS update will replace Qflash with 2MB file support. Second, I have read many reports of @BIOS failing leaving users with dead motherboards and add to that @BIOS reports my motherboard as a Rev 1.0 board so it doesn't fill me with confidence. This only leaves the executable option and hence why I was wondering if the Command prompt option in the Windows boot menu gives me an MS-DOS environment.
Given that my system does work albeit, as it stands, I can't get into BIOS to change settings or be able to get into safe mode when required, it is still usable. If I can't find a way to flash my BIOS with a reasonable degree of confidence, my fallback solution will be to buy a cheap graphics card and install it beside the 670. The cheap card will let me get into BIOS or Windows boot menu when I needed although would be a pain having to switch the connection but I'd live with that rather than risk ending up with a dead motherboard. Given that getting a socket 1366 motherboard now is quite difficult, it could be an expensive experiment (new motherboard, new processor and possibly new CPU cooler fan).
Thanks for your help,