Crosshair II Formula Issues with GTX 260's

Ok... here's my predicament... I just got an ASUS Crosshair II Formula mainboard. I put in my RAM sticks and CPU... runs great. No sweat. I was just doing a quick run, and was using the IGFX for my display. After I cleared all that stuff, I power down, and install both of my GTX 260's... I turn it on... not a damn thing. Everything else was running fine, just no video. It's like the board doesn't recognize the cards are even in the slots. At first, I figured I just bought a bad board. Then, I thought maybe my PSU wasn't pushing enough juice. It's a Thermaltake Black Widow 850W... plenty for this rig. So, I take one card out and run it... still nothing. I flashed to the newest BIOS (ver. 1802), and still no joy. So I get curious... I dig out my old ATI HD 2900XT and this little HD 4670... I plug in the 2900... and it booted right up scribbles and crap on screen, obviously detected... I mean, the card's been fried for months, but I use it for crap like this. it's a 2900XT... this thing was created for the sole purpose of raping your PSU! the 4670 worked fine too... I'm at a total f*cking loss. anyone got an idea?

Thanks,
Jeremy

u said that it detects ati cards like ati 2600xt right? then your pcie video card port reads the gtx 260, u said it runs fine but no video, , , i have a question sir? have you disable the IGFX first before installing the nvidia gtx 260 , maybe try to disable that before installing those gtx 260 cards . . .i have this board and a gtx 260 card and it works for me . . . hope that helps sir ... thanks