EDITED: TRY THIS FIRST and disregard the instructions below. Go to Safari>Preferences>Extensions and for the time being uninstall any extension or extensions you may recently have added. Go to your home folder Library>Safari>Extensions and move any of those to the Trash.
In addition, go to http://www.thesafemac.com/arg-identification/ for instructions. Web Surf Shield isn't specifically listed, but this gives some other places to look for removal.
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Not certain, as this may be something new, but see if this will do it. First disconnect from the Internet, either by removing the Ethernet cable from the computer or turnng off Airport.
Go to Preferences>Security and uncheck Enable JavaScript. If that unlocks Safari, then from the Menubar>Safari>Empty Cache and then Reset Safari, with the following checked.
Once this is done, re-enable JavaScript and reconnect to the Internet.
Do you happen to remember what site you visited when this happened, or did you open some attachment in an email?
Message was edited by: WZZZ