Product Detail Powered by Intel Core 2 Duo E7500/2.93 GHz 4 GB installed memory 320 GB hard drive Windows 7 Professional 64-bit operating system . The "Lenovo ThinkCentre M58 9960 - Tower - 1 x Core 2 Duo E7500 / 2.93 GHz - RAM 4 GB - HDD 1 x 320 GB - DVD-Writer - GMA 4500 - Gigabit Ethernet - Windows 7 Pro 64-bit - Monitor : none - TopSeller - Microsoft Office Ready" is best product for you. We recommended Lenovo ThinkCentre M58 9960 - Tower - 1 x Core 2 Duo E7500 / 2.93 GHz - RAM 4 GB - HDD 1 x 320 GB - DVD-Writer - GMA 4500 - Gigabit Ethernet - Windows 7 Pro 64-bit - Monitor : none - TopSeller - Microsoft Office Ready