The overview says Windows 8, the Specs list says Windows 8.1. So far two reviewers said they had to upgrade to 8.1, while another listed 8.1 as being something they liked about this computer, inferring it came with it already installed. In a question someone else asked about the difference between this model (Model: m7-j120dx) and Model m7-j020dx, an HP Rep responded that this model has Windows 8 and the m7-j020dx has Windows 8.1. This information is rather conflicting. It would seem to me that the m7-j120dx would be a newer version than the m7-j020dx since the model number is one higher, but, again, an HP Rep responded the opposite. Can someone tell me for sure which version of Windows is on this model? Thanks in advance!