Ok people, I am still dealing with this problem after about a year. I have a biostar ta790gx 128M motherboard and its not letting me put all my ram modules in it. It can hold 4, but will only run right with 3. And the weird thing is, if I put 3 in, 2 in orange and 1 in the very last green slot, it does the same as having 4 in them. I have tried a different power supply, I have taken out the video card, I have replaced this motherboard with a new one from biostar, I have tried a dual core athlon processor, and all is the same thing. I have tested the ram in the old board I replaced and no errors came about. I have tried putting the ram at 2.1 and 2.2 voltage and taking the ram speed at 533. If ANYONE can help me get this figured out, I would greatlyyyy appreciate it.