No DVI signal at BIOS. Strange desktop res.

Following an unexplained system crash whilst running 3D benchmark 05, my Hanns G HW191D monitor no longer receives a DVI signal during BIOS posting from my EVGA 8800GTS (320mb, BIOS version 60.80.18.00.02) through its DVI-D single link cable. Confusingly, I do receive a signal at the Windows welcome screen, but I presume this is due to the drivers kicking in. In this situation, any large resolutions don’t scale to my screen and instead require me to scroll around e.g. move to bottom left for start button, bottom right for system time etc

I’m using the newest (non-beta, May6th) drivers, have tried older drivers, still have a normal POST with no error code beeps, and my system is still as stable as ever. I have tried
• A new DVI cable
• Reseating all cards
• Resetting and reflashing the Mobo BIOS (Gigabyte GA-P35-DS3l)
• Testing RAM and starting up with minimum number of components
• Reinstalling XP
• Windows safe mode and VGA safe mode
• Setting the primary graphics adapter to PCI or PCI-e in the BIOS
• Using nVidia control panel to set DVI as primary when I run a VGA and DVI signal from the same card to the same monitor.
• Trying both DVI outputs from my graphics card (currently using a VGA cable with an adapter to plug into either of my 8800’s DVI ports)
• Testing with a 6600GT card.

After getting the same symptoms with this 6600GT, I emailed EVGA requesting a BIOS update thinking that this may be the cause (logic says it doesn’t boot itself up in a digital mode). EVGA said that this probably won’t help, offered me an RMA, but now I see no point in this as my 8800 is fine.

I’m thinking it’s a monitor or a motherboard problem, but unfortunately, I have no suitable spares to test. Have you heard of this type of problem before? Any ideas or recommendations?

Thanks,
Mike

Do you know which type of cable he had, and which type he is now using?....DVI-I, DVI-D, or DVI-A? This link has diagrams of the different cable types http://en.wikipedia.org/wiki/Digital_Visual_Interface

If you could tell me, it could direct my problem into looking at analogue, or digital signals.

Regards,
Mike