if I understand you correctly, pc is able to POST and boot without quadro 4000. with quadro 4000 in pc, you see solid amber light, no display signal. brad is correct to suggest replace cmos battery w a brand new CR2032. also try clear cmos settings by reset RTCRST jumper on motherboard.
hey everyone, I have a 790 tower with an upgraded 500w PSU and a Quadro 4000, I have had the GPU for a couple months and one day I booted up my pc, I got solid amber light, no display signal, no beeps, and I think diagnostic light code 2 3 4, so I don't know if my PCI-E slot is broken or my GPU is, I don't have another pc to check the GPU in so please let me know what the issue is.   thanks.
gpu issue