|Problem may be with the way some browsers allow a smart fill to the address line. Disable that feature in options.|
I like using a good hosts file. http://winhelp2002.mvps.org/hosts.htm to help block sites.
A good router can be set to block sites too.
A good firewall also may block sites.
1/3 of highway deaths are caused by drunks. The rest are by people who can't drive any better than a drunk.