Lenovo ThinkCentre M91p 4480B1U Small Form Factor Desktop (3.1 GHz Core i5-2400 Processor, 4 GB RAM, 500 GB Hard Drive, DVD+/-RW, Windows 7 Professional 64-bit) Intel Core i5 Processor 3.1GHz 4GB DDR3 RAM 500GB Hard Drive Intel HD Graphics 2000 Windows 7 Professional 64-Bit