Yesterday i installed my new Gigabyte 660 OC on mobo MSI Z77-G65 (new bios 10.7)
I use Win 7 Pro and Nvidia newest drivers 310.70
I hooked two displays first is my main monitor LG 23" (FullHD via DVI or HDMI) , second is a TV Sharp 26" (HD resolution) via other DVI using adapter (D-sub-DVI adapter).
Previously I had GTX 280 and two monitors worked simultaneoulsy but now MAIN display until system boot up (until desktop is shown) is black. In the second screen everything is fine from the very start of system.
If i hook only one monitor everything works fine.
LG, main screen is set as a default screen in Windows preferences.