log-in security too tight

I may have mistakenly changed something while checking through my account at Norton the other day. Now, when I go to connect to a my email system, or a newspaper, or even Norton, I have to re-enter all or some of my details again instead of automatically going to the site. How do I change this so my computer will allow these to be remembered, so I don't have to log in again and again.

I know it is a general change that needs to be made as several places already have been affected, requiring me to log in,