Take one of these monitors and the vga cable to another pc.
Verify they both function.
It’s christmas and I have just received a new monitor. The idea was that I could use both monitors at the same time, something I have seen done before. However, whichever monitor has a HDMI plugged into it works fine, and the one with the VGA doesn’t. It can’t be the monitor, and I have two VGAs which both don’t work, so what is the problem and is there an easy fix?