Mine did the same thing. I think it's when I hook the monitor to the on board mb gpu output on the back side of the board. If I hook direct to the graphics card it sends the boot menue at start up. I want to run off the mb hdmi or dvi so I am hdcp compliant so I can watch bluray but it doesn't work. Saddly, I know the problem now. I have to have hybrid sli capable grafics cards since I am using the nf980-g65 msi mb. Now I find out they don't support this anymore so I have to buy older cards like the Geforce 9800 GX2. I see only 8 cards that support this feature. I guess I could just use the hdmi output off the first card and run sli but not hybrid sli. I really wanted this to work so it would save elec! My psu is 1350 watts with 4 HDs and 6 180mm fans and the 4 core amd black. I am using two old 7900s now. Was using 3 7950s but one took a dump and they were acting weird. It's all in the drivers & bios for sure. My case is the cards are not compliant. I can only use 175.16 I hear? or 178.24 for quad sli?
Check your bios to see if you have mgpu turned on or off. if your hooked up to the mgpu. There's a bunch of stuff to set to get it working right at least on my bios. Until I get my new cards I can't run off the mb gpu to enable hybrid sli.
You have to enable dual display to get the other dvi to work. If your using nvidia control panel it's easy. I am still learning since I just installed windows 7 and it is different for sure but much better so far. It installed it's own raid drivers at first install which was real nice.
Without the post or boot on startup you can't get into the bios. Been there and don't like it. Plug your monitor into the mb output and see what happens or visa versa only after tuning the machine & monitor off and unpluging it from the wall. Ps, don't know what you have for a system? I am no expert and learn from trial and error since the instruction books, etc. say nothing. Tom's Hardware is my manual & instruction book for everything.