Yes I tried this option before I came to Intel and tried the latest version.
I'm going to try an earlier driver just to see if it makes any difference.
Since you've just replaced the motherboard I would check all of the connections before going further.
Well that didn't work.
I installed 188.8.131.528 which is the earliest available on the dell site and the same happened.
The display showed up for 10 - 15 seconds and then just crashed.
Did you have any luck inspecting the connections on the motherboard?
Does the display work with only vga graphics installed? I'm assuming that the display works well enough through the Windows install process. :-p
Another thought, not sure how Dell integrates video, but is it built into the board? If so, you might have the AMD accelerator.