Memory Upgrade

I have an Emachines T1110 desktop with an Anaheim-3 Rev. F-motherboard that came supplied with a 168 Pin 256 Mb, PC133 memory module. I recently purchaced another PC133/256 and installed it into my motherboard. My machine does not boot up with it. I switched the modules around putting the new module into the first slot with the same results. The New module is good as I ran it alone and all worked fine. My question is: What must I do to get all 512 Mb to work in my system? Do I need a newmotherboard? Or, do I simply upgrade the bios? Thanks in Advance.