My OS will only Boot on driver version 10.1 and below. If booted with the most current drivers windows gets to the loading screen then blacks out not entering the desktop. I was wondering if anybody could help me update to the newest drivers.
I would give that a try and then install the latest or whatever drivers you want. I am currently still hanging out on 10.4 because the others give me weird issues in Bad Company 2. Stupid ATI drivers. I've heard many people not going past 10.5 for those reasons.
Does it look like the computer is still running, just with no display. The driver clean should fix it. I have seen some very rare cases where the video output get directed to another output that is not connected(it was almost always TV-out, but since you do not have that, try the other dvi port after the screen blank out if driver sweeper does not help). My old 8800GTX does not give any video after sleeping if the screen was turned off. A quick disconnect and reconnect of the dvi cable fixes it.
I am almost sure it will work with the same bios. There is a bit in there that will say "built by ati" as opposed to "powered by ati", but that should not make a difference. I do NOT recommend flashing the card.
however, I have a xfx 5870 with what would be a reference design(should be just like the OEM) and bios if for some reason you do need it.