Won't boot with 2 ram slots populated

I recently bought a 2nd ram stick, but whenever I tried to install it in my computer, the troubleshoot light switches between CPU and DRAM

I discovered that RAM Slot A2 does not work Both RAM Sticks work as I tested both of them in SLOT B2 So, at the moment I am only using one

ramesses riches slot Be sure to separate the RAM modules with one blank slot in between If you are still getting a Beep code Chances are great that by putting the

rama66 slot Also try only one stick of RAM at a time in the first slot that the motherboard manual says to use