So I've been trying to find a solution to this problem. I have 4GB's of memory installed but Windows indicates that only 3.00 GB is usable. I installed x64 version of Windows just so I can have access to that extra memory stick, so it's a little disappointing to not be able to use it.
Specs & Info:
Windows 8 Pro x64
4 x 1GB DDR2 memory installed
NVidia GeForce GT 440 Graphics Card (512Mb)