Sapphire Amd GPU not recognized by Windows 10

[kindatiredofmygpu]

Hey,
I upgraded GPU from an AMD to another AMD, and my new graphics card is not recognized by Windows 10 in the device manager (not hidden devices either). The fans are spinning and leds are on, but if I plug my monitor to GPU, there is no signal. I thought first that my mobo didn't support the new GPU, so I upgraded mobo (and so new mobo can fit, new case) with no luck. I have clean uninstalled all previous drivers and other GPU software, then checked multiple times that there is no trace of any AMD software. When I attempt to install drivers from manufacturers site, specifically for this GPU, it hits with error 173, no hardware detected. I have gone through my BIOS multiple times, but there are no options regarding PCIe slots or primary graphics devices.
My specs:
GPU: Sapphire AMD Radeon R9 280X Dual-X
CPU: Intel i7 2600 3.40GHz
Motherboard: Asus p8Z68-V PRO/GEN3 LGA 1155
RAM 16GB
Windows 10 home 64bit
PSU: Antec 500W (and yes, I know the psu is low power for my GPU, but my system should still recognize the GPU even if the psu is "kind of low" for the GPU. I'm just a little coucious about spending more money on this unsuccessful project).
BIOS version: American Megatrends Inc. 3603, 9.11 2012. (Update maybe? I would prefere not to, since BIOS updates can cause bigger problems..)

Thank you in advance!

 

[Lutfij]

1| How old is your PSU>? Is it as old as the system's processor?
2| You actually know the issue. The lack of power to the system can and will result in what you're seeing. Furthermore it can damage your GPU or worse the entire system.
3| If you think the pseudo new GPU might probably be an unfruitful investment, might want to drop into a neighbor's rig with at least 650W of power at it's disposal to see if the GPU actually works.

 

[kindatiredofmygpu]

The PSU is not as old as the processor. The previous GPU along with my present CPU was powered with a 350W psu. But yeah, it looks like my best shot is a PSU upgrade.
Thanks for answering so fast!

 

[kindatiredofmygpu]

Update to thread!

I just upgraded my PSU to a Seasonic 750W, and the problem was not fixed. What could possibly be the problem?

Thanks in advance!