You can reset the password via Steam.
Help Error You linked this account already to user with name
Yes, and you can reset your password via Steam as well. Not only via E-Mail/Username.
If you want to request a removal of your additional account, write an email to [email protected] - It may take several weeks.
@golannard If you're looking for the location of your FA install, I imagine it's under steam/common/steamapps somewhere. You can find the install directory directly by going to your steam library, rightclicking the supcom FA game, and finding that option that opens the install directory.