I've installed 12 GB of memory on my Windows 7 computer, and yes it is a 64 bit computer. I can see the memory in bios, as well as in the properties of the computer, but when looking in the properties it says "Installed memory (RAM): 12,0 GB (2,93 GB usable)"... I want to use all my memory. I've tried to start msconfig and changed the maximum memory in the Advanced Options under the boot tab to the maximum value, but after each boot it shows up as 0 again.
Screenshot shows the properties of the computer.
EDIT: Solved, solution was to upgrade bios. Pretty weird considering the computer is only one month old or so.