I've built my first PC and it is all up and running however there is a white light lit up on the motherboard and I have no idea why. I've googled it and people are saying it is a VGA error and that their computers wouldn't post. Mine is working as I am writing this post using the PC.
I'm running a Ryzen 5 3600, Gigabyte RTX 2070 Super, 2x8gb RAM, Seasonic Focus GX650.
Depends on what it is and where it is. On the top right area of the board is 4 diagnostic leds, cpu/boot/ram/vga. By far the most common is the 'White light of Death' VGA error. You can get that for any number of varied reasons, but mostly it's some sort of graphics ability error and the gpu doesn't work.
I've seen it fixed with everything from replacing the cmos battery to reseating the gpu to unplugging the pc for a day.
It's also possible to get that if you have a cpu with an igpu and plug into the motherboard ports, not the gpu ports, there really is a gpu issue but you bypass that using the igpu. Most of the no post errors occur on Ryzen platforms with a cpu that has no igpu.