Intel Server Board S5520SC will not see PCI-e video card

Intel Server Board S5520SC will not see PCI-e video card. It did prior to resetting the BIOS. System will not post with a QuadroFX 5600. Tried another video card and nada, no post. If I put in a really cheap PCI-e video card, it will post.

A few years back told me the BIOS workaround to turn off something? one of the two LAN ports?

I forgot their workaround answer. Any ideas?

Thanks in advance.