Bought an RX580 Nitro+ 8GB as it was the best card to run on my older Gigabyte SKT-1155 Z77X-D3H Motherboard (i5 3570k Sandy Bridge). Motherboard is one of the early UEFI mobos. Initially could not the RX580 working, but changed a few settings in BIOS and also flicked the BIOS switch on card to Quiet mode and got it booting. Fans etc. have been running ok up to now. Went to power it on last night and while the Sapphire logo on card is lit up the fans don't spin at all. Tried multiple things so far...running out of ideas. I've flashed the mobo BIOS to latest stable F16 and also tried Beta F18i....tried setting PEG first, UEFI only, disabling CSM, enabling legacy, changing card switch position again etc. etc. PSU is Corsair 650W. Tried it in other PCIEx8 slot with same result. Done all the other obvious stuff...disabled onboard graphics, tried HDMI cables, DVI ETC. Note: card was working perfectly in Star Citizen so it's got to be some BIOS setting but I'm running out of ideas. Flashing card BIOS is a last resort as it was working already...plus I can't actually get card to boot or be detected at all now. Sapphire logo is lit up but odd that fans are not spinning at all now. Card is definitely seated correctly. Power connectors are all seated. Suggestions please?