2405fpw DVI issues - corrupt EDID?

Okay, here's the situation. I have a Gigabyte 7800GTX connected via DVI to a 24" Dell 2405FPW TFT.

Yesterday I installed Win7 and everything went smoothly. After install Win7 detected the 7800GTX and set the res to the monitors native 1920x1200. This remained for a few hours until eventually I made the mistake of downloading the latest Win7 Nvidia drivers and installing them.

After install my Dell was detected as a 'Generic NON PnP Monitor' and the maximum resolution I could select is 1024x768. I've tried rolling back the Nvidia drivers, installed the original MS ones, uninstalled the Nvidia software, tried new monitor drivers, different DVI cables, etc, etc. NOTHING resolves this issue.

On top of that, whenever I now boot I no longer see my BIOS / POST screen unless I plug a different monitor in. For example, if I plug my spare Samsung in (via DVI) the POST screen appears on there, Winlogon will then appear on the Dell. No matter what I do I can't get the POST screen to show on my Dell. On top of this, Win7 will happily detect the Samsung and set it to its native res.

So I Googled a bit and saw some other people with similar issues. I got a DVI > VGA Adapter and plugged that in my 7800 and into the Dell's VGA port. Windows correctly detects this as a 2405fpw and sets the native res as 1920x1200. If I unplug the VGA cable and plug the DVI one into it, Win7 detects it as 'Display Device on DVI' (no mention of Dell 2405fpw). I can also now select 1920x1200. Unfortunately, if I reboot it goes back to 1024x768 and won't go any higher which means I would have to constantly boot up in VGA, then switch the cables over. This, is not acceptable.

To add further insult to injury, the Dell's DVI port now refuses to work on anything other than my Win7 machine. I plugged it into a WinXP machine and it just goes into sleep. The Dells VGA port works fine on the XP maxchine, but absolutely nothing at all shows up over the DVI connection. The mointor just says it's in 'sleep mode' and to move the mouse or press a key (which does nothing). Plug it back into the Win7 machine and it works (albeit at 1024x768)

From what I can gather this is possibly a corrupt EDID, will I be able to fix this? My mate has the same monitor so I was going to ask him to get me the EDID using Phoenix EDID Designer, then write it with Powertstrip.

I understand that Powerstrips 'write EDID' will tell me it's found an EEPROM on port 1 or 2. Which is the port for DVI? I'm assuming port 2?

Thanks