A few years ago I stopped using the software, now retired I want to go back to editing family videos, I have uninstalled the program on the two computers I had, I have reinstalled it on only one but it tells me that the license is already on another computer and it doesn't I can continue with the installation
You will need to deactivate it off of any previous computers. If you don't have access to those computers you can do it through your Magix Account. Most, if not all, of the Sony Vegas Accounts have to transferred to the Magix account under whatever email address you used at the time.