My motherboard will only read one stick of RAM

My motherboard is an Asus M3N72-D.

My memory is KVR800D2K2/4GR



The RAM i bought was dual-channel(2x2GB), and came together in the same packaging. However, my computer is only recognizing one stick of RAM at any given time. I have 4 slots for RAM (A1,B1,A2,B2), and it runs correctly when I put RAM in A1 or B1. The monitor gets no signal when I use A2 or B2 at all, and when using both A1 and B1, it only recognizes one of the slots. I'm wondering if it's something I am doing that is wrong, or if what I got just isn't compatable with what I have.




I'm not positive if I need to give more information, but if I do let me know and I'll do my best.