Q&A: Trying to reinstall the sims 3 pets but it won't let me?

I uninstalled the sims 3 pets and am trying to reinstall it. But when I click the install program factor, the installation wizard thing pops up and asks me “are you positive you want to uninstall all of sims three pets?” I’m thinking I left a thing out when I uninstalled the program. Exactly where must I check to manually delete all traces of sims 3 pets?