I just purchased a used T3610 and it was running fine on BIOS A15. I had seen that it was possible to upgrade storage to an NVME using a pci adapater. I installed the card and everything was working fine so I tried to reinstall windows to the new drive. Installation went fine but when it rebooted it couldn't find the windows installation. I retried the windows installer and it appeared that windows had set up partitions and installed correctly so I assumed it was a BIOS problem.

I was hunting around for some setting that might allow me to boot to the nvme drive (which the bios could detect as a mass storage pci device). I noticed the bios was set to raid so I changed it to ahci. I didn't think this would fix it, but I didn't think it'd hurt. I was wrong. After reboot the computer fails to post and it displays 1, 2, 3 as the error code. Power button is normal. No video is output and fans on the gpu go to max speed.

I've swapped all the ram, tried 4 different video cards in both pci x16 slots. Tried different display devices and ports (hdmi, displayport, dvi). Removed all unnecessary components.

I've also tried removing the CMOS battery and swapping the pwd jumper to the rtcrst pins.

Nothing seems to matter. When I reset the bios, it will power cycle once. I turn it on it begins to post and then it powers off. It powers back on automatically and halts post at 1, 2, 3.

I don't want to believe it's a hardware problem because everything was working until I made the bios change (and I don't want to replace the motherboard), but I'm out of ideas. Can anyone help?