WOW. I HAD THE EXACT SAME THING HAPPEN. My Norton will NOT enable, no matter how much I clik. It displays the ERROR message. Even my Norton icons on the bottom toolbar have disappeared! But here's the worst thing. I CANNOT LOG IN TO ANY ACCOUNT. I can navigate the web to any page, but if I try to login to email, or ebay or whatever, it will not allow me to . All I get is the 'cannot find server' error page when I try logging in to any account.  
Does this sound LIKE a virus?  
Here is my only clue. I downloaded SCREENSAVERS yesterday....haven't been able to look at my email since. Today, i have UNINSTALLED EVERY SCREENSAVER that I downloaded, & rebooted, but doesn't fix my problem. I was thinking that there must be a specific function that is corrupted that ALLOWS me to login to everything. What should I do?
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Here is my only clue. I downloaded screensavers yesterday....haven't been able to look at my email since. Today, i have UNINSTALLED EVERY SCREENSAVER that I downloaded, & rebooted, but doesn't fix my problem. ?