HP Pro 3500 Microtower PC Intel Pentium G2120 3.1GHz 4GB-DDR3 500GB-HDD Windows 7 Professional Microtower Desktop Windows 7 Professional 64 (available through downgrade rights from Windows 8 Pro)install Pentium G2120 Dual Core 3.10 GHz with Intel HD Graphics 2500 4GB DDR3 1333 MHz SDRAM 500GB 7200RPM SATA Hard Drive