Question GPU flashing red/orange ?

[quickcheck]

So I've been running this exact same system for years. Wanted to upgrade to a 5800X3D CPU, hadn't considered I needed to update my bios version, so I put the new CPU in, it didn't boot.

Downloaded new bios, put it on a drive that I've used for bios flashing before, didn't work - seemed like it didn't find the USB drive at all, no flashing lights, nothing.

Thought to myself "well I'll figure that out after NYE", so I put the old CPU in again.
And now it doesn't boot with the exact same hardware as before.

I have tried swapping the RAM sticks around because I remembered that was an issue when I first built this, but to no avail.

The only thing that seems weird to me is my GPU is now flashing orange, I don't have a fishtank case so I can't remember if it did that before.
I am planning to upgrade it but I was waiting for a sale. The GPU is an ASUS ROG 1070. Does the blinking red/orange mean it's dead?
I can only find threads where the system still boots.

Oh, and the BOOT and VGA lights on my Asus B550 Plus motherboard are on. I have removed, cleaned and replaced the GPU multiple times. Power is connected securely, I think.

I'll try and see if it fits in the other PCIe slot but I think I have to remove the entire system from the case.

 

[RealBeast]

Clear the CMOS according to your motherboard directions using the old CPU, then update the bios once you are running stable, then exchange the CPU.

 

[quickcheck]

Clear the CMOS according to your motherboard directions using the old CPU, then update the bios once you are running stable, then exchange the CPU.

Clearing the CMOS had no effect. Still does not boot.

 

[quickcheck]

I transferred half the system to a new case and motherboard, new ram, new cpu (this new mobo is Ryzen 5000 ready).
Same ssd, psu and gpu - exact same problem.

Doesn't seem to boot, no signal to the monitor, top two lights on the mobo are on (boot and vga), gpu is slowly blinking red.
Gpu fans are spinning.
Tried the cmos trick - no effect.

Edit: I've combed through a bunch of Asus GPU threads now and the most frequent issue seems to be the PSU, which is of course weird because it worked fine previously, but it's not the newest so I think I'll just order a new one.