Thank you thats what I've been thinking. Your right plug in the other for video when I want to use it.What Wolf described above is for setting default monitor in Windows. For BIOS, there is no way to do it. For any given set of cables connected to GPU always the same one will be chosen to display BIOS and this cannot be changed. What you can do is connect different set of cables (so in your example, not connecting HDMI) and you will get BIOS on different screen, but again this will be by GPU choice, not yours.
I fiquerd that out.Which display the video card uses for BIOS depends on the video card and how it setup port priority. There's no way to change this priority, so if you want your VGA monitor to show BIOS because it always shows on the HDMI display, you have to disconnect the HDMI display.