Quick sanity check:
Your LG monitor supports resolution only up to 1366 x 768 and has only one D-Sub jack. Your graphic card is build in the motherboard. Official Gigabyte website states that there is no Windows 10 compatible chipset drivers available (I highly doubt that these drivers are backward compatible). Then I am not sure how did you installed drivers for the chipset.
You have AMD compatible motherboard with socket AM2+/AM2 with one of the supported CPU's on board. Most probably you're lucky enough to run on the processor integrated graphics. Otherwise I have no idea how do you even have the video signal on your monitor.
Your main task would be to figure out what is the current working graphics unit - you can find it in the device manager. After that you can go to the
Display adapter properties->Adapter->List all modes->Choose the resolution you want and press OK. Refer to the step 8 of this guide.
I would also advise to downgrade back to Windows 7 or whatever version of Windows, for what you can find drivers for. Otherwise you end up in a situation like your with upgraded OS and lost functionality of your hardware.
Or you can use some third party solutions to hack around and see it will work, but most probably this option will mess something up and you'll find yourself in constant search for fixes.