Lenovo ThinkCentre M73 10B60009US Desktop (3.4 GHz Intel Core i3-4130 Processor, 4 GB RAM, 500 GB Hard Drive, DVD-Writer, Windows 7/8 Pro 64-bit) Black (Discontinued by Manufacturer) 3.4GHz Intel Core i3-4130 Dual-Core Processor (4 threads, 3MB cache); Intel HD Graphics 4400 4GB (16GB Max) DDR3-1600 SDRAM, 500GB 7200rpm SATA 6.0Gb/s Hard Drive, DVD-Writer 2 x USB 3.0, 4 x USB 2.0, Serial, VGA, RJ-45, DisplayPort, 2 x PS/2 Gigabit Ethernet, High Definition (HD) Audio, Internal Speaker (1 Watt), USB Keyboard and USB Optical Mouse Windows 7 Professional 64 preinstalled through downgrade rights in Windows 8 Pro 64-bit; 3 Years Limited Warranty