I am presuming you have a BIOSTAR A320MH motherboard correct? Because the BIOS version you installed is the latest one for that motherboard which gives support and recognizes the 5600G processor.
What was your previous CPU you had installed?
Did you install the latest AMD Graphics driver for your new 5600G from here: https://www.amd.com/en/support/apu/amd-ryzen-processors/amd-ryzen-5-5000-g-series-desktop-processors...
Do you have 2 monitors connected? One to your Nvidia GPU card and the other to the Motherboard Video port?
If only one monitor how is it connected to your computer? to the GPU card or Motherboard video port?
Do you get video output when your first boot up and then lose video when Windows loads or never get video output?
Which version of Windows are you using?