There might be two issues with this:
1) Update your motherboard drivers for the PCI-E chipset.
2) I assume you have Intel integrated in MB, if any other co. makes an intel chipset, they might have their own specific drivers and Intel's will give you an error.
3) Have you gone through your BIOS settings or left everything at default (never recommended for custom setup).
4) Integrated all in one chipsets always had some problems, you might consider RMA the whole MB.
With a decent system like that, I would buy a standalone graphics card. I mean you got the Z68 more expensive and newer MB for a reason right ?