Mozilla does not bundle Thunderbird and Firefox together. Possibly you used some rogue site and may not even have got genuine Firefox & Thunderbird,& could have had all sorts of other unwanted stuff. See * [[Uninstall Firefox from your computer]] * [[Uninstall Thunderbird from your computer]] * [[Troubleshoot Firefox issues caused by malware#w_how-do-i-get-rid-of-malware]]'''_how-do-i-get-rid-of-malware''' * [[How to stay safe on the web]] You should not need to edit registry content to uninstall Mozilla software, and it is generally a bad idea to go near the registry unless you are absolutely certain what you are doing.