Second monitor no longer working after Windows 10 updates

[iamded]

I've had Windows 10 for a while now, thanks to the free upgrade. Initially I ran two monitors, both plugged into my AMD R9-270X graphics card. Recently due to a botched upgrade I was required to reformat and reinstall Windows on my machine, and when I pieced it back together I opted to chuck both of my R9-270X's in.

My primary graphics card, let's call it GPU1, has two DVI plugs, so I initially had both my monitors plugged into this one with the second graphics card in storage. My second R9, let's call it GPU2, has one DVI and one VGA plug, so I can only plug one monitor into that one.
So I pieced it together with GPU1 and GPU2, but this time both monitors worked only when one was plugged into GPU1 and the other was plugged into GPU2. This was fine with me as everything was working.

However, due to complications with the Windows 10 upgrade, my CD key was no longer valid. My old key was due to expire anyway so I picked up a new Windows 10 key but had trouble activating it. I opted to try to reinstall Windows 10 using the official USB stick the key came with, which ran a Windows update thing reinstalled Windows and some drivers or whatever it does. After this update however, only one monitor works at a time.

I've wiped the GPU drivers, reinstalled them, reinstalled the chipset drivers, tried switching between using GPU1 only and using one monitor with each GPU, nothing's working. The screens and the cables are fine because I can switch them out with the first plug on GPU1 and they both work just fine. Rebooting Windows causes the second monitor, when plugged in, to flicker with the Windows logo as green bars streak through it in a glitchy mirror image of the other monitor's pristine Windows boot logo.

I'm happy to supply any more information if needed, it's awfully cramped on this one screen.

EDIT: I eventually came across this AMD Clean-up Utility which removed all the AMD gunk I had left over from multiple Windows reinstalls, and allowed me to restart from scratch. After that, installing the latest driver worked like a charm, for a short while at least. After rebooting I'm back at square one...

EDIT 2: Windows Key + P to access the projection settings and selecting Extend seems to have solved the issue for now.

 

[Laptop_Nerd]

Hi,

Please do try this clean install method that may help. Use the link below for the complete guide and tools you can use.

http://www.tomshardware.com/faq/id-2767677/clean-graphics-driver-install-windows.html

Hopefully this will help.

 

[iamded]

Didn't seem to work.
I ran the clean install as instructed. After rebooting and installing the latest AMD drivers for my card as well as the AMD chipset drivers, both monitors were working and I was happy. I then rebooted to complete the installation and now just the one is working again.
I have my primary monitor plugged into GPU1 and it is working. Secondary monitor is plugged into GPU2 and it is not working, and driving me crazy.
If I unplug the second monitor and plug it into GPU1's second port, neither monitors work. The second monitor's light turns from yellow to blue to signify that it's active, but the screen stays black and empty, and the primary monitor turns off, with the light turning from blue to yellow to indicate it's inactive. I'm baffled.

 

[Colif]

Are you running crossfire?

With a multi-monitor setup, why do some of the displays become disabled when I enable AMD Radeon™ Dual Graphics?

AMD Radeon™ Dual Graphics is a form of AMD CrossFireX™ Technology and with the current solution only displays from the 'master' graphics device (the one that monitors are plugged into) are available. The other displays are disabled. To ensure your displays remain available, make sure to connect your displays to the 'master' graphics device. The 'master' device settings can be found in the AMD VISION Engine Control Center, which is the user interface for the drivers and installation package.

https://community.amd.com/docs/DOC-1318#jive_content_id_With_a_multimonitor_setup_why_do_some_of_the_displays_become_disabled_when_I_enable_AMD_Radeon_Dual_Graphics

 

[iamded]

Thanks Colif, I don't think Crossfire was the problem. I had tried removing one GPU, switching out cables, switching what was plugged into where, wiping and reinstalling drivers, checking the system display setting and the Radeon display settings....

In the end, all I had to do was Windows Key+P and select Extend. Note I had absolutely tried this earlier to no avail, so something I tried between then and now must have changed something to affect this. Either way, problem resolved for now. Thank you all for your help!