Problem with monitors turning off while working. What could be the problem?

Question

Monitors

My main monitor is samsung s24d300, second monitor is philips 150c4. The main vga monitor, the second monitor also bought two hdmi vga adapters for two monitors, after 1-2 hours of work for a PC during the game, two monitors turned off sharply, the PC worked, the buttons glowed on the monitor. But the screens were black, I had to reboot the PC and after that everything worked again. After I decided to buy a vga - dvi d adapter for the second monitor, the first 1-2 hours everything was fine, but again, during the game or the monitor was running, the same problem occurred again. I checked the power of the outlet so that there were no surges, but this did not help either. I also tried to set the same Hz on the monitors - 60 Hz, but it also did not work. No idea what could be the problem