Hi, sorry for the late update. I borrowed a GPU, and when putting it in my motherboard, I got the same result. For some reason, my first thought after this was to try the other PCI-E slot. Not only did the PC post, it booted into my NVMe drive! I took the borrowed GPU out and put in my GPU, and it just works. The second slot is also x16, so I’m just going to leave it in there. Thank you so much for your help!Sounds like the right plan.