Try uninstall Norton and reinstalling in safe mode. The crap has hooked on to your security software. If you have another computer, download AVG free, spybot and install that in safe mode. It's probably not a virus but a spyware bot and they're a bugger to get rid of. You can also get Ewedo from the AVG site but I'm not sure how that works now. It may scan and say "Yep you got something and if you send us money we'll get rid of it" I don't know.
