Hi grimosilla, You should take a look at the Knowledge Base article [[Search bar]]. Your default search might have been changed by a particular site. Sites like MSN, Yahoo, etc have been know to ask to become your homepage and change your search engine. If the address bar search has been changed as well, you might want to take a look at [[Location bar search]]. If that doesn't work you should look at the article [[Preferences are not saved]]. Finally, your issue may be because you've been hit with some [https://support.mozilla.org/en-US/kb/Is%20my%20Firefox%20problem%20a%20result%20of%20malware?s=malware&r=0&e=sph&as=s#w_how-do-i-get-rid-of-malware Malware]. Hopefully this helps!

Matt, thanks much for your response! I had just found the way to make the change, and did.