I have been researching how to mirror display's for a few days now, and it seems to be one of the most difficult things to do, or get an easy answer for. I have Windows 7 64-BIT, SLI GTX 260's & EVGA 750i motherboard. (If that matters) I am trying to mirror my desktop display to my 51" Samsung PN51D7000. I have DVI going from Card 1 to Monitor, and DVI/HDMI adaptor going from Card 1 (output 2) to TV. I got it working for dual displays, extending monitors etc. But I see no option for mirror, cloning or anything. I have updated to latest driver for MB and Video card. What's next?
I'm sorry that nobody replied to your post. Hopefully you're not still having this problem after almost 3 months but in case that you are, I'll tell you what I know. From previous experience, I have seen situations where there wasn't an option to do this and I could never find out why and ended up having to use the video card's driver software. Either way, under
"Control Panel\Appearance and Personalization\Display\Screen Resolution"
you should have a drop down menu by the field 'Multiple Displays' with an option to 'Duplicate These Displays.' That's the option you'd want to select.
But, like I said earlier, that option doesn't exist sometimes for whatever asinine reason I could never discover. So, going through Nvidia Control Panel or ATI Catalyst Control Center was the only way I could get it to work.