Lenovo G550 15.6-Inch Laptop (Black) 2.1 GHz Intel Pentium Dual Core Processor 3 GB DDR3 Memory; 250 GB Hard Drive 3D sound enhancement creates a virtual 3D sound effect, for a more immersive sound experience when watching video or playing games 15.6-inch LED backlight screen and numeric keypad Windows 7 Home Premium operating system