No video signal w/ asus MOBO + 5600 xt GPU

[_Jo_]

The day before putting the rx 5600 xt, i had an rx480 running ok. So after placing my rx 5600xt (with pc unplugged) i boot up and get no video signal at all, power to the Gpu is suposedly being delivered since the gpu LED indicator is off, it heats up and fans work now and then.

I managed to get signal once, by booting up with my HDMI plugged to the MOBO and then after bootup plugging it to the gpu, i got signal and could type my passwd on the user menu in Pop OS. Then went to settings and Pop Os was detecting my card model correctly. After shutting down I never got it to work again. And cant even enter BIOS since i have no signal at all, not even MOBO logo or OS choosing menu. 

 

I tried the GPU on another pc via DisplayPort, and MOBO logo and BIOS are a visible and accesible, but windows bootup also gave black screen. I figured that was a driver or windows issue.

 

 

So my specs are:

-Ryzen 5 3600

-Dual 8gb 2660mhz hyperx ddr4 ram

-Asus Prime b450 plus (pci-e 3.0)(not sure what bios version).

2x 1tb western digital blue HDD

- Sentey epp750-ps 750w 80plus bronze (5+ years old)

- Gygabyte Windforce oc rx 5600xt

OS: Dual boot Windows 10 and POP!_Os, one in each HDD.

 

 

Is the problem a combination of factors? Or is it either Motherboard or old probably unreliable PSU? Motherboard, CPU, and RAM are half a year old or less.