Installed 4g Memory 2g Being Used?

[havokak]

Hi i have installed 4g of memory in my computer and i noticed only 2g was being used anyone know why? Here is mobo and memory. I also have windows 7 64 bit

http://www.newegg.com/Product/Product.aspx?Item=N82E16813131407

http://www.newegg.com/Product/Product.aspx?Item=N82E16820231193

 

[marcellis22]

CTL-ALT-DEL...Windows Task Manager...Check Processes and see what's using up memory.