If it were the board it I wouldn't think it would even get to the Windows 7 start up screen. If it were the board I wouldn't think it would get past post.
It is unliekyly that you have two defective cards but see if you can test them in another rig and find a third card to test with the board. If you have the same results with the third one while the other cards end up testing fin the change the board. This is one reason why I avoid most intel boards (not chip set wise but the board it self from that company)