Question Double monitor setup flickering black/switching on/off only while playing games

[ibuprofen420]

Hi, I have a massive problem that is stopping me from playing the games that I used to. I've tried most things that I could find on the internet and still nothing is working.
So my problem is that when I play games literally any game on a full screen my game will work fine for the first few minutes of playing and then suddenly both of my monitors will start turining on/off / flickering black in kind of weird intervals every few second one monitor will go off and then the other one a sec after and constantly until I turn the game off. What is weird is that it makes a sound as if something is disconecting and connecting back in because it makes the annoying windows sounds.
So far I have tried games like fallout 4, diablo 3, fortnite, cs:go and many others and the problem appears on all of them. What is weird - I can play league of legends normally without this problem but that's the only game that seems to be working.
What is also weird is that I never had that problem few months ago, I did not change anything in my setup, all my drivers are updated, same cables eveything and one day suddenly it started going crazy. I opened my pc and cleaned it properly, everything seems to be working fine and as it was when the games were working so I don't know what the problem is.
Things I tried:

• Formatted my pc completely and installed everything back again
• Tried all the possible nvidia settings solutions that I could find
• All the drivers are updated, even tried going back to older versions of them and still not working
• All the cables are correctly plugged in
• Tried all the games in windowed mode and still the same thing

My setup and facts:

• my main monitor is a SAMSUNG SMS22A100 which is connected through a DVI to VGA (?) pretty sure
• my second monitor is a ACER S220HQL which is connected from DVI (the blue one) to HDMI
• I'm using GeForce GTX 960 everything updated
• windows 10

That's mostly what I can think of, I will answer any questions if you need more information. Any help or advice is appreciated. Also I am not familiar with a lot of PC terms so please keep it simple so I can understand, thanks.

TLDR:
Both my monitors flicker on and off after a certain amount of time, only when playing certain games. It doesn't do it when I am browsing the internet etc. Cables seem to be fine and all the drivers are updated.

 

[Lutfij]

Welcome to the forums, newcomer!

Since you're on Windows 10 and you've mentioned reinstalling the OS, did you fabricate the bootable USB installer using Windows Media Creation Tools? What BIOS version are you on for your motherboard at the time of writing? When you speak of installing all drivers again, are they the latest sourced from manufacturer's support site and installed in an elevated command, i.e, Right click installer>Run as Administrator?

Might want to list the specs to your entire build, like so:
CPU:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:

include the age of the unit and the make and model, not just it's wattage.