Google: Virtual Memory.
If you havnt set your VM (virtual memory) up manually then you really havnt taken your PC out of the box you bought it in.
This works on/for/in XP, Vista, Windows 7. Its not about your OS but is about the hardware. So I assume this will work for the Window 8 users as well.
Learn how to set your PC to its full potential.
Youtube has step by step instructions also.