Incredibly strange 3 monitor problem (cannot get all to display)

On my windows 10 machine with SLI GTX 670's I have been using a 3 monitor setup for years without any problem. All in 1 card I have connected a Samsung SA300 by hdmi, a Asus VG248 and finally by display port a Benq 1440 GW2765. Again I had no problems with them until today when I disabled the first 2 monitors in display settings to test something. Since then I cannot get all 3 to work together.

Whenever I plug in the benq it displays the desktop but the other 2 monitors shut down, whenever i disconnect the benq the other 2 power up and display an extended desktop. No matter what I do I cannot evade this situation. I have no idea why this would happen.

I tried reinstalling my video drivers but that didn't fix the problem.

I should note that in the nvidia control panel it does detect the monitors as connected. Also when i connect the benq and the other 2 monitors shut down, the extend display option is gone (there is only duplicate display) and pressing detect monitors does nothing.

I would really appreciate your help in this matter. Thank you!

I sincerely apologize, I found the solution and it was just an error on my part. You have to click duplicate first, then it shows a 1|2 over 1 monitor icon, then you click the drop down and got extend and it separates 2 monitors out, then repeat this process for the 3rd monitor. Its very strange because initially it doesn't show you all 3 monitors as grey boxes, only 1 main one. Its hard to explain but I got it working. Maybe this will help someone.

Hi,
Where did you click on duplicate, please?

Excellent. Works now. Thanks so much.