How do I completely delete all traces of prior Firefox install? I believe my browser became corrupted. I uninstalled it and then went to the C drive and deleted all associated folders. As far as I know, I have no files saved as webpages but I do not know how to confirm in Windows 10. When I download Firefox I get the message saying a copy has been installed on my computer before. How do I completely remove any trace of Firefox so I can fresh install?