Hi, got allmost same issue. Same setup; DH55HC MB with i3-540 CPU, 4GB 1333 RAM (Kingston) Firts boot on VGA worked fine. I then set the BIOS/CMOS to have the PCIe as primary display. I have the nVidea GTS250 1GB card.
After rebooting just black screen. Does not give me the Bios/Cmos te reconfigure. Boot sounds fine, is just that I can't see anything.
How do you rest back to factory defaults?