1. Press Alt or F10 to see the menu bar
2. Click on Tools >> Preferences >> Security >> Saved Passwords...
3. Just delete the password and Firefox won't login automatic anymore.

What I am concerned about is that Firefox now logs me in without needing to be prompted. It used to only fill in login details after I started to type in my user name. That is useful but now anyone could login to my bank a/c, etc just by going to the site - very unsecure. I know how to turn of or delete passwords as suggested but that is not what I was asking.

It seems that no-one has figured this problem out yet. In the past Firefox only filled in site login details after one started to type in ones user name. Now when one goes to a site the user name and password are already filled in. This would enable anyone using the computer to log in. This makes a nonsense of Firefox having a "secure" password protected folder. This has only happened since the most recent update and needs fixing. Does anyone from Firefox actually read these posts. It would be a great help if one could a some real response and not just a suggestion to browse the forum to see if any other user has the problem.

Details like websites remembering you (log you in automatically) are stored in a cookie.

You can delete to cookies from the website to make the website forget about you.

• Firefox/Tools > Options > Privacy > "Use custom settings for history" > Cookies: "Show Cookies"

You can set the signon.autofillForms pref to false on the about:config page to prevent Firefox from filling form data automatically.

You can open the about:config page via the location/address bar. You can accept the warning and click "I'll be careful" to continue.

• http://kb.mozillazine.org/about:config

That's the answer I needed. Altering the preference did the job. Thanks.

You're welcome.