I purchased Kingston Hyper (KHX1333C7D3K2/4GX) 2x2gb. Installed the 2x2gb and problem is SOLVED!!!
Thank you so much for your help with this.
We now know that -
Gigabyte P55-USB3 Motherboard - Intel P55, Socket LGA1156, ATX, DDR3, PCIe, USB, SATA 3.0Gb/s
compatible or supported yet (as of 2/2/11) with
Corsair CMX4GX3M1A1333C9 XMS3 4GB DDR3 RAM - PC10666, 1333MHz, 4096MB
at least with just 1x4g stick installed.
I am a high school computer instructor and this was a build I was doing with a student. We enjoyed working on this and learned a lot. This was his first experience with a discussion forum. What an amazing first experience for him to have.
Thank you again for your help. Feel free to correct my conclusion if there is something I missed.