When mine died, it ended up being the third PCIe connector on my graphics card going bad. I thought it was the power supply, so my friend brought his over (with only two PCIe connections) anmd it spun up fine, but wouldnt POST without all three connected, so I ordered a replacement and RMAd my power supply. Got the replacement, same problem. Unplugged the third connector, same thing as with my friends PSU. Turned out when the third connector was plugged in, it would trip the PSUs protections and the PSU would keep it from booting to avoid damaging anything.
RMAd the graphics card, worked like new.
This is not an option for me. I got it in 2015 anyway so I've needed a new one for awhile.