Windows 7 prof. Nothing much to say. Rather winding-up or seriousness stop_computer seller. Here I can not complain. The shipment was enough afloat, came a new installation CD Windows 7 Professional (64bit) incl. SP1 from the Microsoft recyclers program. Although the product key stuck somewhat carelessly on a base that was tacked on the bill and the envelope shown on the product image, there is not also, but what the heck. Activation at MS has worked smoothly and exactly that's the, what is at stake here. Therefore, from my 5 of 5 Stars.