I'm not sure where you're getting this information, I was going from the Product Guide on the Intel website.
Intel® Desktop Board DZ68BC — Product Guide
According to page 15:
Unbuffered, non-registered single- or double-sided DIMMs with a voltage rating of 1.65 V or less
Am I mistaken in this?
In response to your previous message, I will check the the BIOS model when I get home, if I can find it written on the board, as I do do not even get far enough in the boot process.
As well, yes I have tried using just one stick (All four sticks, attempted in each slot)
Memory clock speed and voltage (1.5v) are ok. Try removing the CMOS battery and power for 20 minutes.
You may update the BIOS if you have a different working RAM.
Otherwise, ask the memory manufacturer about the density of the memory sticks; they need to match the requirements of the board in the link above.