issues recognising RX550 on older hardware?

[Jackanuke]

I recently bought an RX550 for an old machine (i7-860, 6GB DDR3 Memory, DP55WB MoBo, Win10) to play anime fighters, but when switching from the old (i don't know what model) HD4000 to the RX 550, the machine won't boot and gets stuck at the boot menu (BIOS Settings: <F2>, no other options shown), and pressing F2 just causes the machine to post beep.
I tried both taking out and putting in the CMOS battery, uninstalling the old drivers and installing the new ones, however due to the way AMD handle driver delivery now I cannot simply install the drivers I need without the RX550 being in the machine, and the motherboard lacks a CPU video output. I'm not sure what I need to do to get it working, but if someone could point me I would be very grateful

 

[cin19]

1) Make sure the MB has the newer version BIOS. https://www.intel.com/content/www/us/en/support/products/41162/boards-and-kits/desktop-boards/legacy-intel-desktop-boards/intel-desktop-board-dp55wb.html

2) What PSU did you have? you have to have a 350W at least good PSU for the rx550.

 

[Jackanuke]

PSU is a stock 850W Codegen, I'm aware they're not exactly nice, but I thought it would run. I updated the BIOS and got the same error but with more splash screen options, that all give me POST beeps when pressed. I think I'm just gonna build a new system on Ryzen 3 tbh.

I THINK that the issue with this is a lack of GOP support and maybe formal Legacy options on the DP55WB