I am running:
Asus P5K-E MOBO
Enermax 500W PSU
Corsair XMS2 4GB (2 x 2GB) DDR2 800 (PC2 6400) RAM

My problem:
Computer doesn't boot when both sticks of RAM are inserted. The computer had been running fine with both sticks before I moved and had the computer shipped out to California. How could a month of inactivity and/or shipping cause the computer to suddenly not run the same?

Should I check BIOS settings in terms of the memory speed and voltage? I am pretty inexperience when it comes to tinkering with RAM BIOS settings.

Thanks in advance,
Kevin