How to get my bookmarks, history and topsites back after accidentally uninstalling firefox web browser

In case you haven't checked that checkbox saying something like Removing Profiles, etc. you can restore your profile back. https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data?redirectlocale=en-US&redirectslug=Profiles Find your old Profile and replace your new Profile files with the old profile files.