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After changing the configuration, the second monitor stopped working

I have two monitors. The main monitor is FullHD, works via HDMI. The second HD monitor works through the VGA. Connection diagram: The main monitor is connected to the HDMI video card, the Second monitor is connected to the VGA motherboard.

Previously there was a GTX 650, and an I3-3210 – everything worked. Now I installed GTX 1660 and I5-2400 – both monitors do not want to work at the same time.
If I set the BIOS priority to the integrated graphics, the second monitor works, the main one does not. If I do the opposite, the first monitor works, the second does not.

Replacing with an old CPU did not help. The new video card does not have a VGA output. I heard that both video cards (built-in Intel Graphics 2500 and GTX 1660) cannot work at the same time. What could be the problem?

Note: I did nothing to the system when replacing hardware, only installing a new driver for the video card. OC Windows 7.