Since downloading the update for Firefox 3.6.10 all websites that I previously stayed logged into must be logged into everytime I open them. Why? And can this be fixed?

This has happened with previous Firefox updates but only after the initial update. Once I logged into websites such as facebook, yahoo, hotmail etc. I stayed logged in and was able to access these sites without having to log in each and every time. I have checked all boxes on these and all other sites to remember passwords and to keep me logged in and I still have to log in on each new visit. I rebooted my computer and this did not help. I made sure that Remember Passwords was checked on the Security tab under Options in the Tools for Firefox.