- the BIOS should be set to "PCIE", not "IGFX" (IGFX is the motherboard graphics which you won't use)
- make sure you are connected to the VIDEO CARD
Also, you say you know your graphics card works because OTHER CARDS WORK? That's actually backwards. If you can hook up to OTHER cards and then this card doesn't work then your graphics card is the problem.
Based on what you've said (other graphics cards work) it sounds to me like you have a problem with the graphics card.
I'm sorry I made a mistake. I think it works because other card doesn't work. The other card was new and this one is new too.