It's not a good sign when both are throwing a Code 43.
Windows has stopped this device because it has reported problems. (Code 43)
If it is occuring on both GPUs it could be more than a problem with any individual GPU. Shutdown your computer and take the 590 out. Make sure onboard graphics work and while you're doing this, clean out the 590 and visually inspect it for any issues (blown caps, scorch marks, excessive dust, etc.) If it looks fine, try re-seating it in your machine. After that, I would rule out re-seating the CPU as well. Keep in mind that all of those PCI-E lanes end up at the CPU. If you have more than 1 PCI-E slot that can accommodate the 590 (albeit at slower speeds maybe,) I would give it a try to rule out the PCI-E slot. I would recommend doing this before and after re-seating the CPU as well.