Just so I clear a few things up to make this easier, and possibly solve your issue, I'll ask you a few questions:
Do you have the SLI bridge attached, or have SLI enabled in the Nvidia control panel? You will want to disable SLI and probably remove the bridge as well for your use.
Also, did you right click the windows 7 desktop, click screen resolution, then click detect? This should show all the displays you currently have hooked up and then allow you to organize them.