You have a serious issue if you get not video output at all to be able to make any changes.
Was it working before with Video Output?
Did you upgrade the APU Processor or upgrade any hardware connected to the motherboard?
Are you using a VGA-HDMI Adapter? If so is it a Active VGA-HDMI Adapter?
Personally it sounds like a Monitor cable issue. I would make sure your VGA-HDMI Adapter is "Active" type and not "Passive".
The reason why is because you should get video Output during POST unless you need to configure something in BIOS to get video output or at least when it boots into Windows.
Try doing a CMOS CLEAR on your motherboard to reset the BIOS back to factory defaults and see if you get Video Output during POST.
What is the native Resolution of your Monitor? Make & Model?
Try using a different Monitor and see if you get Video output. Maybe a Monitor with a native VGA Input Port on it.
According to your Gigabyte Motherboard specs it supports Maximum Resolution of 1920 x 1200. So if your Monitor can't support that Resolution than it would not have any video output to it: https://www.gigabyte.com/Motherboard/GA-F2A68HM-S1-rev-10/sp#sp
Make sure you have the last latest BIOS version and CHIPSET drivers installed from Gigabyte Support.
Here is the last AMD APU Driver for your A10-7800 processor: https://www.amd.com/en/support/apu/amd-series-processors/amd-a10-series-apu-for-desktops/a10-7800-ra...
It is possible the latest may not be compatible with your motherboard so here you can try Previous AMD Drivers: https://www.amd.com/en/support/previous-drivers/apu/amd-series-processors/amd-a10-series-apu-for-des...