I keep on randomly experiencing this, either after changes I do to system or just when restarting the system and it all of a sudden decides to fuck itself up for no real reason and based on Google, it seems to be a very common thing with NVIDIA graphic cards and high end ASUS monitors like my ASUS VG248QE (144Hz gaming monitor). Though I’ve seen reports with other brands as well.
It’s a really annoying one because you often don’t think it’s “just this” and you try to exclude countless other things, wasting time when solution for the issue takes just 1 minute of sitting still. Yeah…
When I was experiencing this issue, I’ve disassembled half of my system, tested with backup graphic card (which only happens to have HDMI output, not DisplayPort so I was basically just testing if the rest of the system is working), reinstalled my ASUS Strix GTX 980 and the damn thing wouldn’t output image through DisplayPort to my ASUS VG248QE. When it was connected through HDMI, image was there. Connected through DisplayPort, “No Signal”. I was going mad WTF is going on. Was testing different DisplayPort ports on graphic card, turning monitor on and off using Power button, changing input on monitor, nothing. But nothing changed because one variable in the problem wasn’t really getting changed or “reset”…
Then I figured out yet another dumbest solution to seemingly complex issue…
Unplug monitor from power for 1 minute and then plug it in again. Voila, DisplayPort magically starts working again! How retarded is that eh?
It seems like there is some electronic in monitor that goes haywire here and there and only way to get it unstuck is to cut power to the monitor till all capacitors in it fully discharge. This apparently resets the “problematic” state and it then manages to sync with a graphic card correctly and starts outputting the image again through DisplayPort.
Hope this helps. Just try to remember this as the first “go to” solution when it happens again so you won’t waste time testing everything else… Try this first since it only takes a minute.
Angry Sheep Blog 
Left the Monitor unplug for 3 hours and still does not work with displayport
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There is no need to wait for such long duration because it wouldn’t make any difference. It’s about discharging capacitors and they usually don’t last longer than 1 minute for sure. As for the solving of the issue, it might be something else. Usually it’s DisplayPort cable related. Cheap ones tend to cause problems, but it could be something else. GeForce cards are funny with DisplayPort. My system often refuses to start for no reason with just a white underscore in the middle section of screen. But if I unplug DP cable from GeForce GTX 980 during boot, it starts fine. Go figure…
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I can see it detect the Display via Displayport, but can’t get display to work (no signal) Could be a faulty cable, ill go exchange it tomorrow, will see. but I see lost of people having similar issue with VG248QE.
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Did it work after the exchange?
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Absolutely worked like a charm, while everything else failed!!! Thanks!!!!
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Hello,
Similar configuration for me. So I decided to reply just to build the knowledge for others, or solution (salvation) for us.
Configuration:
Graphics: POSEIDON-GTX980-P-4GD5 connected to:
Monitor Asus 27″ LED VG278HE through DVI
Monitor NEC 20WGX2 Pro through Asus Displayport to DVI converter
TV Philips through HDMI
Basically everything was working well from may 2015 when I assembled this configuration. No problems, even with Displayport. Till driver installation 376.19 December 2016. Now everything blowed up. Plug and unplug does not help, just randomly and very occasionally NEC starts to actually display through this configuration. Plug and unplug makes Asus and Philips to flicker for few seconds and then everything goes black. Unplug Displayport, rest is back to life. Older drivers doesn’t help. So now I have 3 not working display ports. This is crazy world.
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Thanks, this solution helped me even in 2022 lol.
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