After a couple hours of playing, the monitor turns off (no signal), but the sound continues to work - did not wait long, did a reboot, and again all is well.
Answer from: Sergey Zuev:
Computer help via Internet...
Probably something with the video card, maybe it's heating up. First of all stress test your graphics card with FurMark. If it is over 90 degrees then the cooling system has to be cleaned from dust.
You should also check the cables connection to your monitor and from the monitor to your computer.
In general, it is difficult to say anything specific here, because the problem most likely appears spontaneously and after a rather long time.