SpyBot Search & Destroy is likely finding Firefox profile folders that weren't removed when Firefox was uninstalled. Users are given the option when uninstalling Firefox to delete the profiles.
By default on Win 7, the path is C:\Users\%USER%\AppData\Roaming\Mozilla\Firefox\Profiles\********.++++. The ******** is a random alphanumeric and the ++++ will be the name that is given by the user. If the user gives no name, the Default is the default.