Question Main monitor shows no signal after startup, second works fine

[Wasabak]

Yesterday it worked perfectly fine, but after booting pc today, it showed no signal.
I tried switching cables on monitors and also on gpu, same result, and I also tried pluging in DVI Dual link instead of display port, still no result (tried switching input on monitor). I also tried fresh installation of GPU drivers with no result.
Is there somethin more I can do?

 

[Wasabak]

nevermind, it was caused by faulty Windows update, so I had to reinstall it manually... now it works perfectly