"Switch" primary and secondary displays

Hello
I use Windows 10 64 bits Pro fessional
I used to have a "dual screen" configuration with
- a NEC Multisync as Primary display connected to the graphic adapter with HDMI
- an old ACER as second ary display, connected with Display Port

I just bought a new LG display to replace the secondary display - I connected it and installed the driver and associated softwares

But, now, it seems the "secondary" display became the "primary" and I cannot revert to the previous situation

I recognized that the "new" display has some better performances but I want to keep the NEC Multisync as my primary, as it has beter color space than the new LG display - For instance, when I use Photoshop, I want to have the image on the "old" NEC and th e Photoshop panels on the "new" LG

How can I "switch back" to the old situation ?

T hanks for any help

Have a good day

I have a similar setup to you. My other monitor is connected with DP and my primary (4K) monitor is HDMI. I assume that you have tried the Display settings in Windows to make your primary monitor the main display?

Thanks for your answer
After many tries and experiments, I (almost) succeeded in setting my configuration
Still some problems because of different resolution for both screens and unexpected changes during pauses
ButI'll continue investigating each parameter !
Thanks again

My screens are two different resolutions too, 4K and 1080p for primary and secondary monitors respectively. I seem to be able to make it work by setting the main screen's resolution first and setting it to 150% (otherwise reading the screen becomes difficult at 4K). The secondary monitor is 1080p and I just leave all the settings alone for that. Then I set the primary monitor as my main display and that is that. It just works. However, at boot time, my BIOS screen comes up on the secondary monitor because my 3070 ti likes to display on the display port connectors first. Once Windows starts to boot it comes up on the primary monitor just fine.

Keep in mind that my primary monitor is identified as monitor two in the picture I posted above. I just ticked the "Make this my primary display" box.

That is really all you should have to do, unless you have something really funky going on with your setup or graphics driver.