Sims Medieval windows 7 error

Did you have the game installed on your computer at a prior date? Did you uninstall it from this computer at some point? It can happen that traces of the game installation remain on your computer (most often in the registry) and you will have to manually uninstall the game. Here is how you do that:

https://help.ea.com/article/manually-uninstalling-sims-medieval

But please only do this by yourselfe if you are really experienced with computers. If you are not so sure about your computer skills, please ask someone else for help.