I have nforce 2 GA-7N400 motherboard, and had 1Gb matched pair (512) Corsair XMS DDR RAM (supposedly you can install up to 3 Gb), and everything was running fine, but recently decided to put another Gb in the exact same thing in the other two slots. The manual says that the computer is supposed to automatically detect the type and size of the RAM installed, but when I go to check and see if the extra RAM is there it still says 1024. I've tried re-seating the RAM, but the same thing happens so I'm wondering if I'm missing something.
are you 100% sure you have got the same type of memory that you already have, install PCWizard and only install the original RAM (or 1 stick at a time) then compare the RAM section of PCWizard, and look for something like RAM type = DDR 400, do this with each stick of RAM, if they are all the same type you'll then know how to set the BIOS, if there not the same type you'll then know what the problem is
