Dell Optiplex MiniTower Business High Performance Desktop Computer PC (Intel Quad-Core i7-2600 up to 3.8GHz, 16GB DDR3 Memory, 500GB HDD, DVDRW, Windows 7 Professional) (Certified Refurbished) This Certified Refurbished product is tested and certified to look and work like new. The refurbishing process includes functionality testing, basic cleaning, inspection, and repackaging. The product ships with all relevant accessories, a minimum 90-day warranty, and may arrive in a generic box. Only select sellers who maintain a high performance bar may offer Certified Refurbished products on Amazon.com Processor: Intel Core Quad-Core i7-2600S 2.8GHz (Turbo up to 3.8GHz) 6MB Cache 16GB DDR3 (PC3-12800) Memory (4 slots, supports up to 16GB), 500GB 7200 rpm Hard Drive, Intel HD Graphics; SuperMulti DVDRW Drive (Reads and Writes to DVD/CD), USB Keyboard, Mouse, Integrated Audio, 10/100/1000Mbps LAN; Slots: 10 x USB 2.0 ports, 2 x audio-out jacks, 1 x microphone jack, 1 x RJ-45 Ethernet port, 1 x VGA port, 1 x line-in jack, 1 x parallel port, 1 x serial communication port; Windows 7 Professional 64 bit, Activation code is on the tower; the best operating system for business