5870s in Crossfire

I just finished building new rig with dual 5870's on a WS Supercomputer board.  Am using a Cooler Master 1250 PS.  8GB of Corsair Dominator memory and Intel I7 870 stock no oc.  Booted it up with 5870s connected via both Crossfire interconnects and no display. Decided to get it up and running first so took out one card and loaded Windows 7 Enterprise 64bit and got all drivers and updates done.  Reinstalled second card and reconnected the two crossfire connectors, and still no display on boot.
Am I doing something wrong with the interconnects?  Is there some setting in the bios that enables crossfire?  Is there a specific DVI connector that has to be used?  I have never used Crossfire have always used SLI cards.  Any help appreciated.

UPDATE:

Got it fixed.  Downloaded latest drivers from ATi.  Loaded them and Crossfire works.  Guess the native Windows 7 driver won't support it.  Pulled a 7.5 Windows Performance Index.  Was disappointed it was not higher.  The i7 870 and memory with no OC pulled a 7.8.  Appreciate the help.

I see you made a post at ASUS support forums too.

This board correct?  http://www.newegg.com/Product/Product.aspx?Item=N82E16813131594

Have you tried both cards one at a time? maybe you have one dead card.

Try using just one interconnect cable. The two connections are for quad and tri crossfire.

Those connections are not for crossfire. They're for NVIDIA SLI only. Don't use them.

Look at the last picture in this series and see how the connectors are labeled.

Get Crossfire connectors first, then blow the roof off of the gaming world. LOL!