I had Dell XPS 8300 Desktop & had bought & Installed Windows-7 ( Ultimate ) on it is 500 GB HDD.I gave that system to my relative except Hard Drive.Now I bought Dell T-7500 Workstation with only DOS installed on it is hard drive to save some money & because I already have Windows-7 ( Ultimate ) DVD.I took out the hard drive with DOS from the workstation & replaced it with the hard drive that I had i