Make sure to use an 8 pin PCIe power plug, not the twin molex to 8 pin adapter. Makes sure you disabled or switched the primary display device in BIOS to the card if this has onboard video. Obviously make sure the GPU is connected to the display, not the board. Then download the following 2 things DDU and the 20.8.3 driver form these links:
Display Driver Uninstaller Download version 18.0.3.6 (guru3d.com)
Radeon™ RX 480 Previous Drivers | AMD
After downloading and saving those, disconnect form the internet and install DDU but don't run it yet. Boot Windows into safe mode, assuming this is Windows 10 ( 8.1 isn't really supported and there's a different but doable workaround), hold the "shift" key and click "restart". A blue screen will appear and select "advanced", "startup options", it will reboot again to a blue screen with options. Choose "safe mode" and boot into Windows. Now run DDU and remove the previous GPU driver, if it was Nvidia and you tried to install the AMD, you'll want to do this procedure twice, once for Nvidia and once for AMD.
Now that the driver has been removed, remain disconnected from the internet for now. Install the 20.8.3 driver, it should install normally with a reboot. After it reboots, go into the Radeon settings and disable the auto update feature. Newer drivers can be a problem for this GPU. If you're still having issues, please respond with the full system specs.
"It worked before you broke it!"
