HP ProBook L8E17UT#ABA 15.6-Inch Laptop (Black) Intel Core i5 5200U/2.2 GHz Dual-core processor Windows 7 Pro 64-bit (available through downgrade rights from Windows 8.1 Pro Update 64-bit) OS Preinstalled OS : Windows 7 1600 MHz 4 GB DDR3L SDRAM