Question GPU or PSU problem?

Mar 22, 2020
I just finished cleaning my PC. When I tried to turn it on after cleaning it, it wouldn't start anymore.
The ram light just blinks for a bit but wouldn't continue turning on. I did a bunch of research on why it wouldn't turn on,
I did reseat the rams, checked cmos, non-of them worked. Until I read something that the video card maybe the culprit.
I did have a modular power supply so I removed the cable from the GPU to the power supply and it worked, having to connect my Monitor to the mother board.
I did try to use a different cable from the GPU to the power supply and it still wouldn't work.
While the computer is running, I tried plugging in the Video card cable to the power supply, the computer will turned off. If I try plugging the in the Video card to the power supply, before turning it on, it will just blink again, and wouldn't turn on. By the way, I also tried plugging the GPU to a different slot and it still didn't work.
You guys have any idea on how to fix this? Is it a GPU or PSU problem?

I have a 80+ Bronze Seasonic 520 Watts. Been using it for a little over 3 years now. The GPU is an Asus 1060 3GB.