Thomas:
Welcome to Discussions.
As far as I know it is not possible for a spyware program to be installed on your computer without your authorizing it. Your OS will ask you if you want to accept it, and you will have to either enter your password, or if you installed withouth a password, you will have to hit enter or return.
What or who Bigfoot is and what it is doing on your computer I don't know, but, to the best of my knowledge, unless you downloaded an email attachment, it is likely not a virus or spyware.