You don't get a signal to dvi connection since you do not have a Intel HD Graphics capable CPU. Only Core i3's and Core i5-6xx Series CPU's can outpout signal to an H57 Chipset Motherboard like DH57DD. You will need a dedicated graphics card in order to use your systems with your Core i5-750 Quad Core CPU's.
Follow the link below to consult the CPU compatibility list for your Motherboard:
That's sad news for me. Looks like I'll be dusting off my eBay account. Thank you for the info, though.
No problem. Good luck to your system building quests.....