This computer comes loaded with Windows XP Professional SP3 32Bit with a 500GB Hard Drive. The processor has been upgraded from a Pentium D 3.4GHz to a newer and more powerful Intel Core 2 Duo 2.0GHz Processor. This computer has been inspected inside and out to ensure everything is in perfect working condition, included verifying no blown or leaky caps, and cleaning out the computer. Windows XP Professional has been loaded on to the computer and activated. Keyboard and mouse are not included with this sale. Most USB Keyboard or mouse will work with this computer. See What Else Is For Sale!