Control panel> System
OK, so this is where you're seeing it then, right?
And for "Installed memory (RAM)" it shows "4.0GB, 2.75GB usable by Windows"? Is that exactly what it says?
I've never seen that except under a 32-bit OS with more than 2GB of memory. Are you sure
that it says "64-bit Operating System" beside "System type:" as shown in the picture above?